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Recent Articles in Endocrine Reviews

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Kearns AE, Khosla S, Kostenuik P
RANKL and OPG Regulation of Bone Remodeling in Health and Disease.
Endocr Rev. 2007 Dec 5;
Osteoclasts and osteoblasts dictate skeletal mass, structure, and strength via their respective roles in resorbing and forming bone. Bone remodeling is a spatially coordinated lifelong process whereby old bone is removed by osteoclasts and replaced by bone-forming osteoblasts. The refilling of resorption cavities is incomplete in many pathologic states, which leads to a net loss of bone mass with each remodeling cycle. Postmenopausal osteoporosis and other conditions are associated with an increased rate of bone remodeling, which leads to accelerated bone loss and increased risk of fracture. Bone resorption is dependent on a cytokine known as RANKL (receptor activator of nuclear factor kappa B ligand), a TNF (tumor necrosis factor) family member that is essential for osteoclast formation, activity and survival in normal and pathologic states of bone remodeling. The catabolic effects of RANKL are prevented by OPG (osteoprotegerin), a TNF receptor family member that binds RANKL and thereby prevents activation of its single cognate receptor called RANK. Osteoclast activity is likely to depend, at least in part, on the relative balance of RANKL and OPG. Studies in numerous animal models of bone disease show that RANKL inhibition leads to marked suppression of bone resorption and increases in cortical and cancellous bone volume, density and strength. RANKL inhibitors also prevent focal bone loss that occurs in animal models of rheumatoid arthritis and bone metastasis. Clinical trials are exploring the effects of denosumab, a fully human anti-RANKL antibody, on bone loss in patients with osteoporosis, bone metastasis, myeloma, and rheumatoid arthritis. [Abstract/Link to Full Text]

Ben-Jonathan N, Lapensee CR, Lapensee EW
What Can We Learn from Rodents about Prolactin in Humans?
Endocr Rev. 2007 Dec 5;
Prolactin (PRL) is a 23-kDa protein hormone that binds to a single-span membrane receptor, a member of the cytokine receptor superfamily, and exerts its action via several interacting signaling pathways. PRL is a multifunctional hormone that affects multiple reproductive and metabolic functions and is also involved in tumorigenicity. In addition to being a classical pituitary hormone, PRL in humans is produced by many tissues throughout the body where it acts as a cytokine. The objective of this review is to compare and contrast multiple aspects of PRL, from structure to regulation, and from physiology to pathology in rats, mice, and humans. At each juncture, questions are raised whether, or to what extent, data from rodents are relevant to PRL homeostasis in humans. Most current knowledge on PRL has been obtained from studies with rats, and more recently, from the use of transgenic mice. Although this information is indispensable for understanding PRL in human health and disease, there is sufficient disparity in the control of the production, distribution and physiological functions of PRL among these species to warrant careful and judicial extrapolation to humans. [Abstract/Link to Full Text]

Eizirik DL, Cardozo AK, Cnop M
The Role for Endoplasmic Reticulum Stress in Diabetes Mellitus.
Endocr Rev. 2007 Nov 29;
Accumulating evidence suggests that endoplasmic reticulum (ER) stress plays a role in the pathogenesis of diabetes, contributing to pancreatic beta-cell loss and insulin resistance. Components of the unfolded protein response (UPR) play a dual role in beta-cells, acting as beneficial regulators under physiological conditions or as triggers of beta-cell dysfunction and apoptosis under situations of chronic stress. Novel findings suggest that "what makes a beta-cell a beta-cell", i.e., its enormous capacity to synthesize and secrete insulin, is also its "Achilles heel", rendering it vulnerable to chronic high glucose and fatty acid exposure, agents that contribute to beta-cell failure in type 2 diabetes. In this review, we address the transition from physiology to pathology, namely how and why the physiological UPR evolves to a proapoptotic ER stress response and which are the defenses triggered by beta-cells against these challenges. ER stress may also link obesity and insulin resistance in type 2 diabetes. High-fat feeding and obesity induce ER stress in liver, which suppresses insulin signaling via JNK activation. In vitro data suggest that ER stress may also contribute to cytokine-induced beta-cell death. Thus, the cytokines IL-1beta and IFN-gamma, putative mediators of beta-cell loss in type 1 diabetes, induce severe ER stress through, respectively, NO-mediated depletion of ER calcium and inhibition of ER chaperones, thus hampering beta-cell defenses and amplifying the proapoptotic pathways. A better understanding of the pathways regulating ER stress in beta-cells may be instrumental for the design of novel therapies to prevent beta-cell loss in diabetes. [Abstract/Link to Full Text]

Poitout V, Robertson RP
Glucolipotoxicity: Fuel Excess and {beta}-Cell Dysfunction.
Endocr Rev. 2007 Nov 29;
Glucotoxicity, lipotoxicity, and glucolipotoxicity are secondary phenomena that are proposed to play a role in all forms of type 2 diabetes. The underlying concept is that once the primary pathogenesis of diabetes is established, probably involving both genetic and environmental forces, hyperglycemia and very commonly hyperlipidemia ensue and thereafter exert additional damaging or toxic effects on the beta-cell. In addition to their contribution to the deterioration of beta-cell function after the onset of the disease, elevations of plasma fatty acid levels that often accompany insulin resistance may, as glucose levels begin to rise outside of the normal range, also play a pathogenic role in the early stages of the disease. Because hyperglycemia is a prerequisite for lipotoxicity to occur, the term glucolipotoxicity, rather than lipotoxicity, is more appropriate to describe deleterious effects of lipids on beta-cell function. In vitro and in vivo evidence supporting the concept of glucotoxicity is first presented, as well as a description of the underlying mechanisms with an emphasis on the role of oxidative stress. Second, we discuss the functional manifestations of glucolipotoxicity on insulin secretion, insulin gene expression, and beta-cell death; and the role of glucose in the mechanisms of glucolipotoxicity. Finally, we attempt to define the role of these phenomena in the natural history of beta-cell compensation, decompensation, and failure during the course of type 2 diabetes. [Abstract/Link to Full Text]

Donath MY, Størling J, Berchtold LA, Billestrup N, Mandrup-Poulsen T
Cytokines and {beta}-Cell Biology: from Concept to Clinical Translation.
Endocr Rev. 2007 Nov 29;
The tale of cytokines and the beta-cell is a long story, starting with in vitro discovery in 1984, evolving via descriptive and phenomenological studies to detailed mapping of the signalling pathways, gene- and protein expression patterns, molecular and biochemical effector mechanisms to in vivo studies in spontaneously diabetic and transgenic animal models. Only very recently have steps been taken to translate the accumulating compelling preclinical data into clinical trials. The aim of this chapter is to present an overview of early and recent key observations from our own groups as well as other laboratories that serve to illuminate the road from concept to clinical translation. [Abstract/Link to Full Text]

Biondi B, Cooper DS
The Clinical Significance of Subclinical Thyroid Dysfunction.
Endocr Rev. 2007 Nov 8;
Subclinical thyroid disease (SCTD) is defined as serum FT4 and FT3 levels within their respective reference ranges in the presence of abnormal serum thyrotropin-stimulating hormone levels. Subclinical thyroid disease is being diagnosed more frequently in clinical practice in young and middle-aged people as well as in the elderly. However, the clinical significance of subclinical thyroid dysfunction is much debated. Subclinical hyper- and hypothyroidism can have repercussions on the cardiovascular system and bone, as well as on other organs and systems. However, the treatment and management of SCTD and population screening are controversial despite the potential risk of progression to overt disease, and there is no consensus on the thyroid hormone and thyrotropin cutoff values at which treatment should be contemplated. Opinions differ regarding tissue effects, symptoms and signs, and the cardiovascular risk. Here we critically review the data on the prevalence and progression of SCTD, its tissue effects, and its prognostic implications. We also examine the mechanisms underlying tissue alterations in SCTD and the effects of replacement therapy on progression and tissue parameters. Lastly, we address the issue of the need to treat slight thyroid hormone deficiency or excess in relation to the patient's age. [Abstract/Link to Full Text]

Hill JO
Understanding and addressing the epidemic of obesity: an energy balance perspective.
Endocr Rev. 2006 Dec;27(7):750-61.
The intent of this paper is to address the obesity epidemic, which is a term used to describe the sudden and rapid increase in obesity rates that began in the 1980s and continues unabated today. Since 1980, the entire population, regardless of starting weight, is gradually gaining weight. This has led to escalating obesity rates and to obesity being considered one of the most serious public health challenges facing the world. At one level, the obesity epidemic is a classic gene-environment interaction where the human genotype is susceptible to environmental influences that affect energy intake and energy expenditure. It is also a problem of energy balance. Understanding the etiology of obesity requires the study of how behavioral and environmental factors have interacted to produce positive energy balance and weight gain. Reversing the epidemic of obesity will require modifying some combination of these factors to help the population achieve energy balance at a healthy body weight. While body weight is strongly influenced by biological and behavioral factors, changes in the environment promoting positive energy balance have been most responsible for the obesity epidemic. Our best strategy for reversing the obesity epidemic is to focus on preventing positive energy balance in the population through small changes in diet and physical activity that take advantage of our biological systems for regulating energy balance. Simultaneously, we must address the environment to make it easier to make better food and physical activity choices. This is a very long-term strategy for first stopping and then reversing the escalating obesity rates, but one that can, over time, return obesity rates to pre-1980s levels. [Abstract/Link to Full Text]

Farooqi S, O'Rahilly S
Genetics of obesity in humans.
Endocr Rev. 2006 Dec;27(7):710-18.
Considerable attention has focused on deciphering the hypothalamic pathways that mediate the behavioral and metabolic effects of leptin. We and others have identified several single gene defects that disrupt the molecules in the leptin-melanocortin pathway causing severe obesity in humans. In this review, we consider these human monogenic obesity syndromes and discuss how far the characterization of these patients has informed our understanding of the physiological role of leptin and the melanocortins in the regulation of human body weight and neuroendocrine function. [Abstract/Link to Full Text]

Foster-Schubert KE, Cummings DE
Emerging therapeutic strategies for obesity.
Endocr Rev. 2006 Dec;27(7):779-93.
The rising tide of obesity is one of the most pressing health issues of our time, yet existing medicines to combat the problem are disappointingly limited in number and effectiveness. Fortunately, a recent burgeoning of mechanistic insights into the neuroendocrine regulation of body weight provides an expanding list of molecular targets for novel, rationally designed antiobesity pharmaceuticals. In this review, we articulate a set of conceptual principles that we feel could help prioritize among these molecules in the development of obesity therapeutics, based on an understanding of energy homeostasis. We focus primarily on central targets, highlighting selected strategies to stimulate endogenous catabolic signals or inhibit anabolic signals. Examples of the former approach include methods to enhance central leptin signaling through intranasal leptin delivery, use of superpotent leptin-receptor agonists, and mechanisms to increase leptin sensitivity by manipulating SOCS-3, PTP-1B, ciliary neurotrophic factor, or simply by first losing weight with traditional interventions. Techniques to augment signaling by neurochemical mediators of leptin action that lie downstream of at least some levels of obesity-associated leptin resistance include activation of melanocortin receptors or 5-HT2C and 5-HT1B receptors. We also describe strategies to inhibit anabolic molecules, such as neuropeptide Y, melanin-concentrating hormone, ghrelin, and endocannabinoids. Modulation of gastrointestinal satiation and hunger signals is discussed as well. As scientists continue to provide fundamental insights into the mechanisms governing body weight, the future looks bright for development of new and better antiobesity medications to be used with diet and exercise to facilitate substantial weight loss. [Abstract/Link to Full Text]

Murphy KG, Dhillo WS, Bloom SR
Gut peptides in the regulation of food intake and energy homeostasis.
Endocr Rev. 2006 Dec;27(7):719-27.
Gut hormones signal to the central nervous system to influence energy homeostasis. Evidence supports the existence of a system in the gut that senses the presence of food in the gastrointestinal tract and signals to the brain via neural and endocrine mechanisms to regulate short-term appetite and satiety. Recent evidence has shown that specific gut hormones administered at physiological or pathophysiological concentrations can influence appetite in rodents and humans. Gut hormones therefore have an important physiological role in postprandial satiety, and gut hormone signaling systems represent important pharmaceutical targets for potential antiobesity therapies. Our laboratory investigates the role of gut hormones in energy homeostasis and has a particular interest in this field of translational research. In this review we describe our initial studies and the results of more recent investigations into the effects of the gastric hormone ghrelin and the intestinal hormones peptide YY, pancreatic polypeptide, glucagon-like peptide-1, and oxyntomodulin on energy homeostasis. We also speculate on the role of gut hormones in the future treatment of obesity. [Abstract/Link to Full Text]

Cone RD
Studies on the physiological functions of the melanocortin system.
Endocr Rev. 2006 Dec;27(7):736-49.
The melanocortin system refers to a set of hormonal, neuropeptidergic, and paracrine signaling pathways that are defined by components that include the five G protein-coupled melanocortin receptors; peptide agonists derived from the proopiomelanocortin preprohormone precursor; and the endogenous antagonists, agouti and agouti-related protein. This signaling system regulates a remarkably diverse array of physiological functions including pigmentation, adrenocortical steroidogenesis, energy homeostasis, natriuresis, erectile responses, energy homeostasis, and exocrine gland secretion. There are many complex and unique aspects of melanocortin signaling, such as the existence of endogenous antagonists, the agouti proteins, that act at three of the five melanocortin receptors. However, there is an aspect of melanocortin signaling that has facilitated highly reductionist approaches aimed at understanding the physiological functions of each receptor and peptide: in contrast to many peptides, the melanocortin agonists and antagonists are expressed in a limited number of very discrete locations. Similarly, the melanocortin receptors are also expressed in a limited number of discrete locations where they tend to be involved in rather circumscribed physiological functions. This review examines my laboratory's participation in the cloning of the melanocortin receptors and characterization of their physiological roles. [Abstract/Link to Full Text]

Trujillo ME, Scherer PE
Adipose tissue-derived factors: impact on health and disease.
Endocr Rev. 2006 Dec;27(7):762-78.
The endocrine functions of the adipose organ are widely studied at this stage. The adipose organ, and in particular adipocytes, communicate with almost all other organs. Although some adipose tissue pads assume the functions as distinct "miniorgans," adipocytes can also be present in smaller numbers interspersed with other cell types. Although fat pads have the potential to have a significant systemic impact, adipocytes may also affect neighboring tissues through paracrine interactions. These local or systemic effects are mediated through lipid and protein factors. The protein factors are commonly referred to as adipokines. Their expression and posttranslational modifications can undergo dramatic changes under different metabolic conditions. Due to the fact that none of the mutations that affect adipose tissue trigger embryonic lethality, the study of adipose tissue physiology lends itself to genetic analysis in mice. In fact, life in the complete absence of adipose tissue is possible in a laboratory setting, making even the most extreme adipose tissue phenotypes genetically amenable to be analyzed by disruption of specific genes or overexpression of others. Here, we briefly discuss some basic aspects of adipocyte physiology and the systemic impact of adipocyte-derived factors on energy homeostasis. [Abstract/Link to Full Text]

Handschin C, Spiegelman BM
Peroxisome proliferator-activated receptor gamma coactivator 1 coactivators, energy homeostasis, and metabolism.
Endocr Rev. 2006 Dec;27(7):728-35.
Many biological programs are regulated at the transcriptional level. This is generally achieved by the concerted actions of several transcription factors. Recent findings have shown that, in many cases, transcriptional coactivators coordinate the overall regulation of the biological programs. One of the best-studied examples of coactivator control of metabolic pathways is the peroxisome proliferator-activated receptor coactivator 1 (PGC-1) family. These proteins are strong activators of mitochondrial function and are thus dominant regulators of oxidative metabolism in a variety of tissues. The PGC-1 coactivators themselves are subject to powerful regulation at the transcriptional and posttranslational levels. Recent studies have elucidated the function of the PGC-1 coactivators in different tissues and have highlighted the implications of PGC-1 dysregulation in diseases such as diabetes, obesity, cardiomyopathy, or neurodegeneration. [Abstract/Link to Full Text]

Ohnemus U, Uenalan M, Inzunza J, Gustafsson JA, Paus R
The hair follicle as an estrogen target and source.
Endocr Rev. 2006 Oct;27(6):677-706.
For many decades, androgens have dominated endocrine research in hair growth control. Androgen metabolism and the androgen receptor currently are the key targets for systemic, pharmacological hair growth control in clinical medicine. However, it has long been known that estrogens also profoundly alter hair follicle growth and cycling by binding to locally expressed high-affinity estrogen receptors (ERs). Besides altering the transcription of genes with estrogen-responsive elements, 17beta-estradiol (E2) also modifies androgen metabolism within distinct subunits of the pilosebaceous unit (i.e., hair follicle and sebaceous gland). The latter displays prominent aromatase activity, the key enzyme for androgen conversion to E2, and is both an estrogen source and target. Here, we chart the recent renaissance of estrogen research in hair research; explain why the hair follicle offers an ideal, clinically relevant test system for studying the role of sex steroids, their receptors, and interactions in neuroectodermal-mesodermal interaction systems in general; and illustrate how it can be exploited to identify novel functions and signaling cross talks of ER-mediated signaling. Emphasizing the long-underestimated complexity and species-, gender-, and site-dependence of E2-induced biological effects on the hair follicle, we explore targets for pharmacological intervention in clinically relevant hair cycle manipulation, ranging from androgenetic alopecia and hirsutism via telogen effluvium to chemotherapy-induced alopecia. While defining major open questions, unsolved clinical challenges, and particularly promising research avenues in this area, we argue that the time has come to pay estrogen-mediated signaling the full attention it deserves in future endocrinological therapy of common hair growth disorders. [Abstract/Link to Full Text]

Yang SN, Berggren PO
The role of voltage-gated calcium channels in pancreatic beta-cell physiology and pathophysiology.
Endocr Rev. 2006 Oct;27(6):621-76.
Voltage-gated calcium (CaV) channels are ubiquitously expressed in various cell types throughout the body. In principle, the molecular identity, biophysical profile, and pharmacological property of CaV channels are independent of the cell type where they reside, whereas these channels execute unique functions in different cell types, such as muscle contraction, neurotransmitter release, and hormone secretion. At least six CaValpha1 subunits, including CaV1.2, CaV1.3, CaV2.1, CaV2.2, CaV2.3, and CaV3.1, have been identified in pancreatic beta-cells. These pore-forming subunits complex with certain auxiliary subunits to conduct L-, P/Q-, N-, R-, and T-type CaV currents, respectively. beta-Cell CaV channels take center stage in insulin secretion and play an important role in beta-cell physiology and pathophysiology. CaV3 channels become expressed in diabetes-prone mouse beta-cells. Point mutation in the human CaV1.2 gene results in excessive insulin secretion. Trinucleotide expansion in the human CaV1.3 and CaV2.1 gene is revealed in a subgroup of patients with type 2 diabetes. beta-Cell CaV channels are regulated by a wide range of mechanisms, either shared by other cell types or specific to beta-cells, to always guarantee a satisfactory concentration of Ca2+. Inappropriate regulation of beta-cell CaV channels causes beta-cell dysfunction and even death manifested in both type 1 and type 2 diabetes. This review summarizes current knowledge of CaV channels in beta-cell physiology and pathophysiology. [Abstract/Link to Full Text]

de Groot JW, Links TP, Plukker JT, Lips CJ, Hofstra RM
RET as a diagnostic and therapeutic target in sporadic and hereditary endocrine tumors.
Endocr Rev. 2006 Aug;27(5):535-60.
The RET gene encodes a receptor tyrosine kinase that is expressed in neural crest-derived cell lineages. The RET receptor plays a crucial role in regulating cell proliferation, migration, differentiation, and survival through embryogenesis. Activating mutations in RET lead to the development of several inherited and noninherited diseases. Germline point mutations are found in the cancer syndromes multiple endocrine neoplasia (MEN) type 2, including MEN 2A and 2B, and familial medullary thyroid carcinoma. These syndromes are autosomal dominantly inherited. The identification of mutations associated with these syndromes has led to genetic testing to identify patients at risk for MEN 2 and familial medullary thyroid carcinoma and subsequent implementation of prophylactic thyroidectomy in mutation carriers. In addition, more than 10 somatic rearrangements of RET have been identified from papillary thyroid carcinomas. These mutations, as those found in MEN 2, induce oncogenic activation of the RET tyrosine kinase domain via different mechanisms, making RET an excellent candidate for the design of molecular targeted therapy. Recently, various kinds of therapeutic approaches, such as tyrosine kinase inhibition, gene therapy with dominant negative RET mutants, monoclonal antibodies against oncogene products, and nuclease-resistant aptamers that recognize and inhibit RET have been developed. The use of these strategies in preclinical models has provided evidence that RET is indeed a potential target for selective cancer therapy. However, a clinically useful therapeutic option for treating patients with RET-associated cancer is still not available. [Abstract/Link to Full Text]

Pissios P, Bradley RL, Maratos-Flier E
Expanding the scales: The multiple roles of MCH in regulating energy balance and other biological functions.
Endocr Rev. 2006 Oct;27(6):606-20.
Melanin-concentrating hormone (MCH) is a cyclic peptide originally identified as a 17-amino-acid circulating hormone in teleost fish, where it is secreted by the pituitary in response to stress and environmental stimuli. In fish, MCH lightens skin color by stimulating aggregation of melanosomes, pigment-containing granules in melanophores, cells of neuroectodermal origin found in fish scales. Although the peptide structure between fish and mammals is highly conserved, in mammals, MCH has no demonstrable effects on pigmentation; instead, based on a series of pharmacological and genetic experiments, MCH has emerged as a critical hypothalamic regulator of energy homeostasis, having effects on both feeding behavior and energy expenditure. [Abstract/Link to Full Text]

Turgeon JL, Carr MC, Maki PM, Mendelsohn ME, Wise PM
Complex actions of sex steroids in adipose tissue, the cardiovascular system, and brain: Insights from basic science and clinical studies.
Endocr Rev. 2006 Oct;27(6):575-605.
Recent publications describing the results of the Women's Health Initiative (WHI) and other studies reporting the impact of hormone therapy on aging women have spurred reexamination of the broad use of estrogens and progestins during the postmenopausal years. Here, we review the complex pharmacology of these hormones, the diverse and sometimes opposite effects that result from the use of different estrogenic and progestinic compounds, given via different delivery routes in different concentrations and treatment sequence, and to women of different ages and health status. We examine our new and growing appreciation of the role of estrogens in the immune system and the inflammatory response, and we pose the concept that estrogen's interface with this system may be at the core of some of the effects on multiple physiological systems, such as the adipose/metabolic system, the cardiovascular system, and the central nervous system. We compare and contrast clinical and basic science studies as we focus on the actions of estrogens in these systems because the untoward effects of hormone therapy reported in the WHI were not expected. The broad interpretation and publicity of the results of the WHI have resulted in a general condemnation of all hormone replacement in postmenopausal women. In fact, careful review of the extensive literature suggests that data resulting from the WHI and other recent studies should be interpreted within the narrow context of the study design. We argue that these results should encourage us to perform new studies that take advantage of a dialogue between basic scientists and clinician scientists to ensure appropriate design, incorporation of current knowledge, and proper interpretation of results. Only then will we have a better understanding of what hormonal compounds should be used in which populations of women and at what stages of menopausal/postmenopausal life. [Abstract/Link to Full Text]

Cools M, Drop SL, Wolffenbuttel KP, Oosterhuis JW, Looijenga LH
Germ cell tumors in the intersex gonad: old paths, new directions, moving frontiers.
Endocr Rev. 2006 Aug;27(5):468-84.
The risk for the development of germ cell tumors is an important factor to deal with in the management of patients with disorders of sex development (DSD). However, this risk is often hard to predict. Recently, major progress has been made in identifying gene-products related to germ cell tumor development (testis-specific protein-Y encoded and octamer binding transcription factor 3/4) and in recognizing early changes of germ cells (maturation delay, preneoplastic lesions, and in situ neoplasia). The newly recognized "undifferentiated gonadal tissue" has been identified as a gonadal differentiation pattern bearing a high risk for the development of gonadoblastoma. It is expected that the combination of these findings will allow for estimation of the risk for tumor development in the individual patient (high risk/intermediate risk/low risk). This article reviews the recent literature regarding the prevalence of germ cell tumors in patients with DSD. Some major limitations regarding this topic, including a confusing terminology referring to the different forms of intersex disorders and unclear criteria for the diagnosis of malignant germ cells at an early age (maturation delay vs. early steps in malignant transformation) are discussed. Thereafter, an overview of the recent advances that have been made in our knowledge of germ cell tumor development and the correct diagnosis of early neoplastic lesions in this patient population is provided. A new classification system for patients with DSD is proposed as a tool to refine our insight in the prevalence of germ cell tumors in specific diagnostic groups. [Abstract/Link to Full Text]

Gillam MP, Molitch ME, Lombardi G, Colao A
Advances in the treatment of prolactinomas.
Endocr Rev. 2006 Aug;27(5):485-534.
Prolactinomas account for approximately 40% of all pituitary adenomas and are an important cause of hypogonadism and infertility. The ultimate goal of therapy for prolactinomas is restoration or achievement of eugonadism through the normalization of hyperprolactinemia and control of tumor mass. Medical therapy with dopamine agonists is highly effective in the majority of cases and represents the mainstay of therapy. Recent data indicating successful withdrawal of these agents in a subset of patients challenge the previously held concept that medical therapy is a lifelong requirement. Complicated situations, such as those encountered in resistance to dopamine agonists, pregnancy, and giant or malignant prolactinomas, may require multimodal therapy involving surgery, radiotherapy, or both. Progress in elucidating the mechanisms underlying the pathogenesis of prolactinomas may enable future development of novel molecular therapies for treatment-resistant cases. This review provides a critical analysis of the efficacy and safety of the various modes of therapy available for the treatment of patients with prolactinomas with an emphasis on challenging situations, a discussion of the data regarding withdrawal of medical therapy, and a foreshadowing of novel approaches to therapy that may become available in the future. [Abstract/Link to Full Text]

Schäffler A, Müller-Ladner U, Schölmerich J, Büchler C
Role of adipose tissue as an inflammatory organ in human diseases.
Endocr Rev. 2006 Aug;27(5):449-67.
Reviews on the inflammatory role of adipose tissue outside the field of metabolism are rare. There is increasing evidence provided by numerous basic research studies from nearly all internal medicine subspecializations that adipocytes and adipocytokines are involved in primary inflammatory processes and diseases. Therefore, it is the aim of the present review to discuss and to summarize the current knowledge on the inflammatory role of adipocytokines and special types of regional adipocytes such as retroorbital, synovial, visceral, subdermal, peritoneal, and bone marrow adipocytes in internal medicine diseases. Future clinical and therapeutic implications are discussed. [Abstract/Link to Full Text]

Wang H, Dey SK, Maccarrone M
Jekyll and hyde: two faces of cannabinoid signaling in male and female fertility.
Endocr Rev. 2006 Aug;27(5):427-48.
Mammalian reproduction is a complicated process designed to diversify and strengthen the genetic complement of the offspring and to safeguard regulatory systems at various steps for propagating procreation. An emerging concept in mammalian reproduction is the role of endocannabinoids, a group of endogenously produced lipid mediators, that bind to and activate cannabinoid receptors. Although adverse effects of cannabinoids on fertility have been implicated for years, the mechanisms by which they exert these effects were not clearly understood. With the identification of cannabinoid receptors, endocannabinoid ligands, their key synthetic and hydrolytic pathways, and the generation of mouse models missing cannabinoid receptors, a wealth of information on the significance of cannabinoid/endocannabinoid signaling in spermatogenesis, fertilization, preimplantation embryo development, implantation, and postimplantation embryonic growth has been generated. This review focuses on various aspects of the endocannabinoid system in male and female fertility. It is hoped that a deeper insight would lead to potential clinical applications of the endocannabinoid signaling as a target for correcting infertility and improving reproductive health in humans. [Abstract/Link to Full Text]

Cozar-Castellano I, Fiaschi-Taesch N, Bigatel TA, Takane KK, Garcia-Ocaña A, Vasavada R, Stewart AF
Molecular control of cell cycle progression in the pancreatic beta-cell.
Endocr Rev. 2006 Jun;27(4):356-70.
Type 1 and type 2 diabetes both result from inadequate production of insulin by the beta-cells of the pancreatic islet. Accordingly, strategies that lead to increased pancreatic beta-cell mass, as well as retained or enhanced function of islets, would be desirable for the treatment of diabetes. Although pancreatic beta-cells have long been viewed as terminally differentiated and irreversibly arrested, evidence now indicates that beta-cells can and do replicate, that this replication can be enhanced by a variety of maneuvers, and that beta-cell replication plays a quantitatively significant role in maintaining pancreatic beta-cell mass and function. Because beta-cells have been viewed as being unable to proliferate, the science of beta-cell replication is undeveloped. In the past several years, however, this has begun to change at a rapid pace, and many laboratories are now focused on elucidating the molecular details of the control of cell cycle in the beta-cell. In this review, we review the molecular details of cell cycle control as they relate to the pancreatic beta-cell. Our hope is that this review can serve as a common basis and also a roadmap for those interested in developing novel strategies for enhancing beta-cell replication and improving insulin production in animal models as well as in human pancreatic beta-cells. [Abstract/Link to Full Text]

Daftary GS, Taylor HS
Endocrine regulation of HOX genes.
Endocr Rev. 2006 Jun;27(4):331-55.
Hox genes have a well-characterized role in embryonic development, where they determine identity along the anteroposterior body axis. Hox genes are expressed not only during embryogenesis but also in the adult, where they are necessary for functional differentiation. Despite the known function of these genes as transcription factors, few regulatory mechanisms that drive Hox expression are known. Recently, several hormones and their cognate receptors have been shown to regulate Hox gene expression and thereby mediate development in the embryo as well as functional differentiation in the adult organism. Estradiol, progesterone, testosterone, retinoic acid, and vitamin D have been shown to regulate Hox gene expression. In the embryo, the endocrine system directs axial Hox gene expression; aberrant Hox gene expression due to exposure to endocrine disruptors contributes to the teratogenicity of these compounds. In the adult, endocrine regulation of Hox genes is necessary to enable such diverse functions as hematopoiesis and reproduction; endocrinopathies can result in dysregulated HOX gene expression affecting physiology. By regulating HOX genes, hormonal signals utilize a conserved mechanism that allows generation of structural and functional diversity in both developing and adult tissues. This review discusses endocrine Hox regulation and its impact on physiology and human pathology. [Abstract/Link to Full Text]

López-Soriano J, Chiellini C, Maffei M, Grimaldi PA, Argilés JM
Roles of skeletal muscle and peroxisome proliferator-activated receptors in the development and treatment of obesity.
Endocr Rev. 2006 May;27(3):318-29.
Metabolic disturbances associated with alterations in lipid metabolism, such as obesity, type 2 diabetes, and syndrome X, are becoming more and more prominent in Western societies. Despite extensive research in such pathologies and their molecular basis, we are still far from completely understanding how these metabolic perturbations are produced and interrelate and, consequently, how to treat them efficiently. The discovery that adipose tissue is, in fact, an endocrine tissue able to secrete active molecules related to lipid homeostasis--the adipokines--has dramatically changed our understanding of the molecular events that take place in such diseases. This knowledge has been further improved by the discovery of peroxisome proliferator-activated receptors and their ligands, at present commonly used for the clinical treatment of lipid disturbances. However, a key point remains to be solved, and that is the role of muscle lipid metabolism, notably because of the main role played by this tissue in the development of such pathologies. In addition, a reciprocal regulation between adipose tissue and skeletal muscle has been proposed. New discoveries on the role of peroxisome proliferator-activated receptor-delta in skeletal muscle functions as well as the secretory capabilities of muscle, now considered as an endocrine tissue, have changed the general point of view on lipid homeostasis, opening new and promising doors for the treatment of lipid disorders. [Abstract/Link to Full Text]

Woodhouse LJ, Mukherjee A, Shalet SM, Ezzat S
The influence of growth hormone status on physical impairments, functional limitations, and health-related quality of life in adults.
Endocr Rev. 2006 May;27(3):287-317.
The availability of recombinant human GH and somatostatin analogs has resulted in widespread treatment for adults with GH deficiency (GHD) and those with GH excess (acromegaly). Despite being at opposite ends of the spectrum in terms of their GH/IGF-I axis, both of these populations experience overlapping somatic impairments. Adults with untreated GHD have low circulating levels of IGF-I that manifest as altered body composition with increased fat and reduced lean body and skeletal muscle mass. At the other end of the spectrum, adults with GH excess, who have elevated levels of IGF-I, also have altered body composition. Impairments that result from disorders of either GHD or GH excess are both associated with increased functional limitations, such as reduced ability to walk quickly for prolonged periods, and poorer health-related quality of life (HR-QoL). Adults with untreated GHD and GH excess both commonly complain of excessive fatigue that seems to be associated more with impaired aerobic than muscular performance. Several studies have documented that administration of GH or somatostatin analogs to adults with GHD or GH excess, respectively, ameliorates abnormal biochemical profile and the associated somatic impairments. However, whether these improvements translate into improved physical function in adults with GHD or GH excess remains largely unknown, and their impact on HR-QoL controversial. Review of placebo-controlled trials to date suggests that GH and somatostatin analogs have greater effects on gas exchange and aerobic performance than as anabolic agents on skeletal muscle mass and function. Future investigations should include dose-response studies to establish the optimal combination of pharmacological agents plus exercise required to improve not only biochemical markers but also physical function and HR-QoL in adults with GHD or GH excess. [Abstract/Link to Full Text]

Cohen PE, Pollack SE, Pollard JW
Genetic analysis of chromosome pairing, recombination, and cell cycle control during first meiotic prophase in mammals.
Endocr Rev. 2006 Jun;27(4):398-426.
Meiosis is a double-division process that is preceded by only one DNA replication event to produce haploid gametes. The defining event in meiosis is prophase I, during which chromosome pairs locate each other, become physically connected, and exchange genetic information. Although many aspects of this process have been elucidated in lower organisms, there has been scant information available until now about the process in mammals. Recent advances in genetic analysis, especially in mice and humans, have revealed many genes that play essential roles in meiosis in mammals. These include cell cycle-regulatory proteins that couple the exit from the premeiotic DNA synthesis to the progression through prophase I, the chromosome structural proteins involved in synapsis, and the repair and recombination proteins that process the recombination events. Failure to adequately repair the DNA damage caused by recombination triggers meiotic checkpoints that result in ablation of the germ cells by apoptosis. These analyses have revealed surprising sexual dimorphism in the requirements of different gene products and a much less stringent checkpoint regulation in females. This may provide an explanation for the 10-fold increase in meiotic errors in females compared with males. This review provides a comprehensive analysis of the use of genetic manipulation, particularly in mice, but also of the analysis of mutations in humans, to elucidate the mechanisms that are required for traverse through prophase I. [Abstract/Link to Full Text]

Karavitaki N, Cudlip S, Adams CB, Wass JA
Craniopharyngiomas.
Endocr Rev. 2006 Jun;27(4):371-97.
Craniopharyngiomas are rare, mainly sellar/parasellar, epithelial tumors diagnosed during childhood or adult life. Histologically, two primary subtypes have been recognized (adamantinomatous and papillary) with an as yet, unclarified pathogenesis. They may present with a variety of manifestations (neurological, visual, and hypothalamo-pituitary). Despite their benign histological appearance, they often show an unpredictable growth pattern, which, combined with the lack of randomized studies, poses significant difficulties in the establishment of an optimal therapeutic protocol. This should focus on the prevention of recurrence(s), improvement of survival, reduction of the significant disease and treatment-related morbidity (endocrine, visual, hypothalamic, neurobehavioral, and cognitive), and preservation of the quality of life. Currently, surgical excision followed by external beam irradiation, in cases of residual tumor, is the main treatment option. Intracystic irradiation or bleomycin, stereotactic radiosurgery, or radiotherapy and systemic chemotherapy are alternative approaches; their place in the management plan remains to be assessed in adequately powered long-term trials. Apart from the type of treatment, the identification of clinical and imaging parameters that will predict patients with a better prognosis is difficult. The central registration of patients with these challenging tumors may provide correlates between treatments and outcomes and establish prognostic factors at the pathological or molecular level that may further guide us in the future. [Abstract/Link to Full Text]

Nigro J, Osman N, Dart AM, Little PJ
Insulin resistance and atherosclerosis.
Endocr Rev. 2006 May;27(3):242-59.
The epidemic of obesity in the developed world over the last two decades is driving a large increase in type 2 diabetes and consequentially setting the scene for an impending wave of cardiovascular morbidity and mortality. It is only now being recognized that the major antecedent of type 2 diabetes, insulin resistance with its attendant syndrome, is the major underlying cause of the susceptibility to type 2 diabetes and cardiovascular disease. In metabolic tissues, insulin signaling via the phosphatidylinositol-3-kinase pathway leads to glucose uptake so that in insulin resistance a state of hyperglycemia occurs; other factors such as dyslipidemia and hypertension also arise. In cardiovascular tissues there are two pathways of insulin receptor signaling, one that is predominant in metabolic tissues (mediated by phosphatidylinositol-3-kinase) and another being a growth factor-like pathway (mediated by MAPK); the down-regulation of the former and continued activity of the latter pathway leads to atherosclerosis. This review addresses the metabolic consequences of the insulin resistance syndrome, its relationship with atherosclerosis, and the impact of insulin resistance on processes of atherosclerosis including insulin signaling in cells of the vasculature. [Abstract/Link to Full Text]

Hillhouse EW, Grammatopoulos DK
The molecular mechanisms underlying the regulation of the biological activity of corticotropin-releasing hormone receptors: implications for physiology and pathophysiology.
Endocr Rev. 2006 May;27(3):260-86.
The CRH receptor (CRH-R) is a member of the secretin family of G protein-coupled receptors. Wide expression of CRH-Rs in the central nervous system and periphery ensures that their cognate agonists, the family of CRH-like peptides, are capable of exerting a wide spectrum of actions that underpin their critical role in integrating the stress response and coordinating the activity of fundamental physiological functions, such as the regulation of the cardiovascular system, energy balance, and homeostasis. Two types of mammal CRH-R exist, CRH-R1 and CRH-R2, each with unique splicing patterns and remarkably distinct pharmacological properties, but similar signaling properties, probably reflecting their distinct and sometimes contrasting biological functions. The regulation of CRH-R expression and activity is not fully elucidated, and we only now begin to fully understand the impact on mammalian pathophysiology. The focus of this review is the current and evolving understanding of the molecular mechanisms controlling CRH-R biological activity and functional flexibility. This shows notable tissue-specific characteristics, highlighted by their ability to couple to distinct G proteins and activate tissue-specific signaling cascades. The type of activating agonist, receptor, and target cell appears to play a major role in determining the overall signaling and biological responses in health and disease. [Abstract/Link to Full Text]

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Recent Articles in Endocrinology

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Svendsen AM, Vrecl M, Ellis TM, Heding A, Kristensen JB, Wade JD, Bathgate RA, De Meyts P, Nøhr J
Cooperative binding of insulin-like peptide 3 to a dimeric relaxin family peptide receptor 2.
Endocrinology. 2007 Dec 6; .
Insulin-like peptide 3 (INSL3) binds to a G-protein-coupled receptor (GPCR) called relaxin family peptide receptor 2 (RXFP2). RXFP2 belongs to the leucine-rich repeat (LRR)-containing subgroup (LGRs) of class A GPCRs. Negative cooperativity has recently been demonstrated in other members of the LGR subgroup. In this work, the kinetics of INSL3 binding to HEK293 cells stably transfected with RXFP2 (HEK293-RXFP2) have been investigated in detail in order to study if negative cooperativity occurs and if this receptor functions as a dimer. Our results show that negative cooperativity is present, and that INSL3-RXFP2 binding shows both similarities and differences with insulin binding to the insulin receptor. A dose-response curve for the negative cooperativity of INSL3 binding had a reverse bell-shape reminiscent of that seen for the negative cooperativity of insulin binding to its receptor. This suggests that binding of INSL3 may happen in a trans- rather than in a cis way in a receptor dimer. BRET(2) experiments confirmed that RXFP2 forms constitutive homodimers. Heterodimerization between RXFP2 and RXFP1 was also observed. [Abstract/Link to Full Text]

Hong MH, Sun H, Jin CH, Chapman M, Hu J, Chang W, Burnett K, Rosen J, Negro-Vilar A, Miner JN
Cell-specific activation of the human skeletal {alpha}-actin by androgens.
Endocrinology. 2007 Dec 6;
Although it is evident that androgens increase muscle mass and strength, little is known about the critical molecular targets of androgens in skeletal muscle. In rodents, the skeletal alpha-actin gene is a tissue-specific gene only expressed in the levator ani, and other skeletal muscles, but not in the prostate or preputial gland, the well-known androgen target tissue. We have identified tissue-specific androgen-regulated genes in the skeletal muscle in rats following oral administration of androgens and focused on androgen-dependent up-regulation of the skeletal alpha-actin gene. To investigate the mechanism of action, an in vitro system with various cell lines and a series of deletion mutants of the alpha-actin promoter were utilized. The human skeletal alpha-actin promoter was activated by androgens in the muscle cell line C2C12, but not in the liver, prostate or breast cancer cell lines where exogenous human androgen receptor expressed. The sequence of the promoter is sufficient for cell-specific androgen response, providing a model for the tissue specificity demonstrated in vivo. Using a series of deletion mutants, the androgen response can be maintained using just the proximal promoter region. The importance of androgen regulation of this small portion of the human skeletal alpha-actin promoter was demonstrated by the correlation between muscle and the alpha-actin promoter activity for an array of selective androgen receptor modulators (SARMs), including an orally active SARM LGD2226. Taken together, the results suggest that the regulation of skeletal alpha-actin by androgens/SARMs may represent an important model system for understanding androgen anabolic action in the muscle. [Abstract/Link to Full Text]

Belo NO, Sairam MR, Dos Reis AM
Impairment of the natriuretic peptide system in follitropin receptor knockout mice and reversal by estradiol: implications for obesity-associated hypertension in menopause.
Endocrinology. 2007 Dec 6;
Estrogen is considered a major regulator of adipose tissue in females. Estrogen increases circulating levels of Atrial Natriuretic Peptide (ANP), a hormone with renal and cardiovascular effects. The aim of this study was to determine the status of Natriuretic Peptide System in female follitropin-receptor knockout mice (FORKO) that could be associated with obesity and hypertension observed in these mutants. Furthermore, estradiol treatment was used to reverse alterations observed. FORKO and Wild-type (WT) mice received daily injections of Estradiol (E2) for 4 days. On the 5th day, blood was collected for determination of plasma ANP levels and selected tissues were collected for determination of ANP, natriuretic peptide receptor type-A (NPR-A) and type-C (NPR-C) gene expression by RT-PCR and binding of (125)I-ANP by autoradiography. At five months of age, FORKO were heavier and had more adipose tissue than WT. FORKO had lower plasma ANP levels and atrial ANP gene expression, and higher renal and adipocyte NPR-C gene expression than WT. E2 treatment reduced weight gain and increased atrial ANP synthesis as well as decreased ANP clearance receptors, resulting in elevation of circulating ANP level. In conclusion, this study shows that FORKO females have an impaired natriuretic peptide system, which may contribute to the susceptibility of FORKO to developing age-related hypertension previously shown in these animals. This study establishes a relation between estrogen, adipose tissue and ANP, which may have important implications in menopausal women. [Abstract/Link to Full Text]

Montessuit C, Papageorgiou I, Lerch R
Nuclear receptors agonists improve insulin responsiveness in cultured cardiomyocytes through enhanced signaling and preserved cytoskeletal architecture.
Endocrinology. 2007 Dec 6;
Insulin resistance is the failure of insulin to stimulate the transport of glucose into its target cells. A highly regulatable supply of glucose is important for cardiomyocytes to cope with situations of metabolic stress. We recently observed that isolated adult rat cardiomyocytes become insulin resistant in vitro. Insulin resistance is combated at the whole body level with agonists of the nuclear receptor complex PPARgamma/RXR. We investigated the effects of PPARgamma/RXR agonists on the insulin-stimulated glucose transport and on insulin signaling in insulin-resistant adult rat cardiomyocytes. Treatment of cardiomyocytes with ciglitazone, a PPARgamma agonist, or 9-cis retinoic acid (RA), a RXR agonist, increased insulin- and metabolic stress-stimulated glucose transport, while agonists of PPARalpha or PPARbeta/delta had no effect. Stimulation of glucose transport in response to insulin requires the phosphorylation of the signaling intermediate Akt on the residues Thr308 and Ser473 and, downstream of Akt, AS160 on several Thr and Ser residues. Phosphorylation of Akt and AS160 in response to insulin was lower in insulin resistant cardiomyocytes. However, treatment with 9-cis RA markedly increased phosphorylation of both proteins. Treatment with 9-cis RA also led to better preservation of microtubules in cultured cardiomyocytes. Disruption of microtubules in insulin-responsive cardiomyocytes abolished insulin-stimulated glucose transport and reduced phosphorylation of AS160, but not Akt. Metabolic stress-stimulated glucose transport also involved AS160 phosphorylation in a microtubule dependent manner. Thus the stimulation of glucose uptake in response to insulin or metabolic stress is dependent in cardiomyocytes on the presence of intact microtubules. [Abstract/Link to Full Text]

Oliveira JF, Henkes LE, Ashley RL, Purcell SH, Smirnova NP, Veeramachaneni DN, Anthony RV, Hansen TR
Expression of ISGs in extrauterine tissues during early pregnancy in sheep is the consequence of endocrine IFN-{tau} release from the uterine vein.
Endocrinology. 2007 Dec 6;
The ruminant conceptus synthesizes and secretes interferon-tau (IFN-tau), which presumably acts via an intra-uterine paracrine mechanism to signal maternal recognition of pregnancy. The aims of this study were to determine: if Interferon-Stimulated Genes (ISGs), such as ISG15 and OAS-1 are differentially expressed in blood cells circulating in the uterus of ewes; if extrauterine components of the reproductive tract, such as the corpus luteum (CL) also express mRNA for these ISGs; and if antiviral activity is greater in uterine vein than in uterine artery during early pregnancy. The concentrations of mRNA for both ISGs were significantly greater (P<0.0001) in endometrium and jugular blood of 15-day pregnant ewes than in nonpregnant ewes. ISG15 and OAS-1 mRNA concentrations were also greater (P<0.05) in CL from 15-day pregnant ewes than in nonpregnant ewes. Immunohistochemistry revealed intense staining for ISG15 in large luteal cells on day 15 of pregnancy. Blood cells from uterine artery and vein of 15-day pregnant ewes had similar ISG15 and OAS-1 mRNA concentrations, suggesting that these cells were not conditioned by IFN-tau within the uterus. By using an antiviral assay, uterine venous blood was found to contain 500-1000-fold higher concentrations of bioactive IFN-tau than in uterine arterial blood on day 15 of pregnancy. It is concluded that uterine vein releases IFN-tau, which induces ISGs in extrauterine tissues such as the CL during the time of maternal recognition of pregnancy. [Abstract/Link to Full Text]

Augustine RA, Grattan DR
Induction of central leptin resistance in hyperphagic pseudopregnant rats by chronic prolactin infusion.
Endocrinology. 2007 Dec 6;
Pregnancy in rats is associated with hyperphagia, increased fat deposition and elevated plasma leptin concentrations. Elevated leptin would be expected to inhibit food intake, but hypothalamic leptin resistance develops around midpregnancy, allowing hyperphagia to be maintained and excess energy to be stored as fat in preparation for future metabolic demands of lactation. To investigate the hormonal mechanisms inducing leptin resistance during pregnancy, the anorectic response to leptin was examined during pseudopregnancy. Pseudopregnant rats have identical hormonal profiles to early pregnancy, but no placenta formation, allowing differentiation of maternal and placental hormone effects on appetite. To investigate the effect of leptin on food intake, day 9 pseudopregnant rats were injected with leptin (4 microg) via an intracerebroventricular (icv) cannula, and then food intake measured 24 hours later. Pseudopregnant rats were hyperphagic but had normal anorectic responses to leptin. We therefore hypothesized that a longer exposure time to high concentrations of progesterone might be required to mimic the leptin resistance that occurs on day 14 of pregnancy. Pseudopregnant rats were given progesterone to prolong pseudopregnancy beyond the time that leptin resistance develops during pregnancy. However, rats remained responsive to icv leptin. To model the placental lactogen secretion that occurs during pregnancy, pseudopregnant rats were given progesterone and chronic icv ovine prolactin (oPRL) infusion. Central icv injection of leptin had no effect on food intake in pseudopregnant rats receiving chronic oPRL. These results suggest that chronically high lactogen levels, secreted by the placenta during the second half of pregnancy, induce central leptin resistance. [Abstract/Link to Full Text]

Hadjiyanni I, Baggio LL, Poussier P, Drucker DJ
Exendin-4 modulates diabetes onset in non obese diabetic mice.
Endocrinology. 2007 Dec 6;
Activation of the glucagon-like peptide-1 receptor is associated with expansion of beta-cell mass due to stimulation of cell proliferation and induction of anti-apoptotic pathways coupled to beta-cell survival. Although the GLP-1R agonist Exenatide (exendin-4) is currently being evaluated in subjects with type 1 diabetes, there is little information available about the efficacy of GLP-1R activation for prevention of experimental type 1 diabetes. We examined the consequences of exendin-4 (Ex-4) administration (100 ng once daily and 2 microg twice daily) on diabetes onset in NOD mice beginning at either 4 or 9 weeks of age prior to the onset of diabetes. Ex-4 treatment for 26 weeks (2 microg twice daily) initiated at 4 weeks of age delayed the onset of diabetes (P = 0.007). Ex-4-treated mice also exhibited a significant reduction in insulitis scores, enhanced beta-cell mass and improved glucose tolerance. Although GLP-1R mRNA transcripts were detected in spleen, thymus, and lymph nodes from NOD mice, Ex-4 treatment was not associated with significant changes in the numbers of CD4+ or CD8+ T cells, or B cells in the spleen. However, Ex-4 treatment resulted in an increase in the number of CD4+ and CD8+ T cells in the lymph nodes and a reduction in the numbers of CD4+CD25+Foxp3+ Regulatory T cells in the thymus but not in lymph nodes. These findings demonstrate that sustained GLP-1R activation in the absence of concomitant immune intervention may be associated with modest but significant delay in diabetes onset in a murine model of type 1 diabetes. [Abstract/Link to Full Text]

Nagashima T, Maruyama T, Uchida H, Kajitani T, Arase T, Ono M, Oda H, Kagami M, Masuda H, Nishikawa S, Asada H, Yoshimura Y
Activation of SRC kinase and phosphorylation of STAT5 are required for decidual transformation of human endometrial stromal cells.
Endocrinology. 2007 Dec 6;
Progesterone induces decidual transformation of estrogen-primed human endometrial stromal cells (hESCs), critical for implantation and maintenance of pregnancy, through activation of many signaling pathways involving protein kinase A and STAT5. We have previously shown that activation of SRC kinase is closely associated with decidualization and that SRC is indispensable for maximal decidualization in mice. To address whether SRC kinase activity is essential for decidualization in humans, hESCs were infected with adenoviruses carrying EGFP alone (Ad-EGFP), a kinase-inactive dominant negative mutant (Ad-SRC/K295R), or an inactive autophosphorylation site mutant (Ad-SRC/Y416F). The cells were cultured in the presence of estradiol and progesterone (EP) to induce decidualization, and subjected to RT-PCR, immunoblot, and ELISA analyses. Ad-EGFP-infected hESCs exhibited decidual transformation and up-regulation of decidualization markers including IGF binding protein 1 (IGFBP1) and prolactin in response to 12-day treatment with EP. In contrast, hESCs infected with Ad-SRC/K295R remained morphologically fibroblastoid without production of IGFBP1 and prolactin even after EP treatment. Ad-SRC/Y416F displayed similar but less inhibitory effects on decidualization compared to Ad-SRC/K295R. During decidualization, STAT5 was phosphorylated on tyrosine 694, a well-known SRC phosphorylation site. Phosphorylation was markedly attenuated by Ad-SRC/K295R, but not Ad-EGFP. These results indicate that the SRC-STAT5 pathway is essential for decidualization of hESCs. [Abstract/Link to Full Text]

Prast J, Saleh L, Husslein H, Sonderegger S, Helmer H, Knöfler M
Human chorionic gonadotrophin stimulates trophoblast invasion through ERK and AKT signalling.
Endocrinology. 2007 Dec 6;
Chorionic gonadotrophin (CG) is indispensable for human pregnancy since it controls implantation, decidualisation and placental development. However, its particular role in the differentiation process of invasive trophoblasts has not been fully unravelled. Here, we demonstrate that the hormone promotes trophoblast invasion and migration in different trophoblast model systems. RT-PCR and Western blot analyses revealed expression of the LH/CG receptor in trophoblast cell lines and different trophoblast primary cultures. In vitro, CG increased migration and invasion of trophoblastic SGHPL-5 cells through uncoated and Matrigel-coated transwells, respectively. The hormone also increased migration of first trimester villous explant cultures on collagen I. Proliferation of the trophoblast cell line and of villous explant cultures measured by cumulative cell numbers and in situ BrdU labelling, respectively, was unaffected by CG. Addition of the hormone activated ERK-1/2 and AKT in SGHPL-5 cells and pure, extravillous trophoblasts. Inhibition of MEK/ERK and PI3K/AKT blocked phosphorylation of the kinases and attenuated CG-dependent invasion of SGHPL-5 cells. Similarly, the inhibitors decreased hormone-stimulated migration in villous explant cultures. Western blot analyses and gelatin zymography suggested that CG increased MMP-2 protein levels and activity in both culture systems. Inhibition of ERK or AKT diminished CG-induced MMP-2 expression. In summary, the data demonstrate that CG promotes trophoblast invasion and migration through activation of ERK and AKT signalling involving their downstream effector MMP-2. Since the increase of CG during the first trimester of pregnancy correlates with rising trophoblast motility, the hormone could be a critical regulator of the early invasion process. [Abstract/Link to Full Text]

Edwards SJ, Reader KL, Lun S, Western A, Lawrence S, McNatty KP, Juengel JL
The co-operative effect of GDF9 and BMP15 on granulosa cell function is modulated primarily through BMP Receptor II.
Endocrinology. 2007 Dec 6;
Growth and differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15, GDF9B) are oocyte-derived proteins essential for the growth and function of ovarian follicles. Moreover, ovine (o) GDF9 and oBMP15 co-operate to increase both (3)H-thymidine incorporation and alpha-inhibin production, and to inhibit progesterone production by rat or ovine granulosa cells. Although the receptors through which these proteins act individually have been determined, the receptor(s) involved in mediating the co-operative effects of GDF9 and BMP15 is (are) unknown. In this study, the effects of the extracellular domains of the Type I and Type II TGFbeta receptors on (3)H-thymidine incorporation by rat granulosa cells stimulated by oGDF9 and oBMP15 were investigated. Stimulation of (3)H-thymidine incorporation was completely blocked by the BMP receptor II (BMPRII) extracellular domain but unaffected by any other Type II or any Type I receptor. These results suggest that the initial interaction of oGDF9 and oBMP15 is with BMPRII and that a type I receptor is either recruited or already associated with BMPRII in order to mediate the cooperative effects of these growth factors. [Abstract/Link to Full Text]

Vulliemoz NR, Xiao E, Xia-Zhang L, Rivier J, Ferin M
Astressin B, a non selective CRH receptor antagonist, prevents the inhibitory effect of Ghrelin on LH pulse frequency in the ovariectomized rhesus monkey.
Endocrinology. 2007 Dec 6;
Administration of ghrelin, a key peptide in the regulation of energy homeostasis, has been shown to decrease LH pulse frequency while concomitantly elevating cortisol levels. Because increased endogenous CRH release in stress is associated with an inhibition of reproductive function, we have tested here whether pulsatile LH decrease following ghrelin may reflect an activated HPA axis and be prevented by a CRH antagonist. After a 3h baseline LH pulse frequency monitoring, 5 adult OVX rhesus monkeys received a 5h- saline (protocol 1) or ghrelin infusion (100microg bolus followed by 100microg/h, protocol 2). In protocols 3 and 4, animals were given astressin B, a non specific CRH receptor antagonist (0.45mg/kg im), 90 min prior to ghrelin or saline infusion. Blood samples were taken every 15 min for LH measurements, while cortisol and GH were measured every 45 min. Mean LH pulse frequency during the 5h ghrelin infusion was significantly lower than in all other treatments (p<0.05) and when compared to the baseline period (p<0.05). Pretreatment with astressin B prevented the decrease. Ghrelin stimulated cortisol and GH secretion, while astressin B pretreatment prevented the cortisol, but not the GH, release. Our data indicate that CRH release mediates the inhibitory effect of ghrelin on LH pulse frequency and suggest that the inhibitory impact of an insufficient energy balance on reproductive function may in part be mediated by the HPA axis. [Abstract/Link to Full Text]

Chowdhury VS, Yamamoto K, Saeki I, Hasunuma I, Shimura T, Tsutsui K
Melatonin Stimulates the Release of Growth Hormone and Prolactin by a Possible Induction of the Expression of Frog Growth Hormone-Releasing Peptide (fGRP) and Its Related Peptide-2 (fGRP-RP-2) in the Amphibian Hypothalamus.
Endocrinology. 2007 Dec 6;
We recently identified a novel hypothalamic neuropeptide stimulating GH release in bullfrogs and termed it frog GH-releasing peptide (fGRP). The fGRP precursor encodes fGRP and its related peptides (fGRP-RP-1, -RP-2, and -RP-3) and fGRP-RP-2 also stimulates GH and PRL release. Cell bodies and terminals containing these neuropeptides are localized in the suprachiasmatic nucleus (SCN) and median eminence (ME), respectively. To understand the physiological role of fGRP and fGRP-RP-2, we investigated the mechanisms that regulate the expression of these neuropeptides. This study shows that melatonin induces the expression of fGRP and fGRP-RPs in bullfrogs. Orbital enucleation combined with pinealectomy (Ex plus Px) decreased the expression of fGRP precursor mRNA and content of mature fGRP and fGRP-RPs in the diencephalon including the SCN and ME. Conversely, melatonin administration to Ex plus Px bullfrogs increased dose-dependently their expressions. The expression of fGRP precursor mRNA was photoperiodically controlled and increased under short-day photoperiods, when the nocturnal duration of melatonin secretion increases. To clarify the mode of melatonin action on the induction of fGRP and fGRP-RPs, we further demonstrated the expression of Mel1b, a melatonin receptor subtype, in SCN neurons expressing fGRP precursor mRNA. Finally, we investigated circulating GH and PRL levels after melatonin manipulation, because fGRP and fGRP-RP-2 stimulate the release of GH and GH/PRL, respectively. Ex plus Px decreased plasma GH and PRL concentrations, whereas melatonin administration increased these hormone levels. These results suggest that melatonin induces the expression of fGRP and fGRP-RP-2, thus stimulating the release of GH and PRL in bullfrogs. [Abstract/Link to Full Text]

Kinsey-Jones JS, Li XF, Luckman SM, O'Byrne KT
Effects of kisspeptin-10 on the electrophysiological manifestation of gonadotropin-releasing hormone pulse generator activity in the female rat.
Endocrinology. 2007 Dec 6;
Kisspeptins are extraordinarily potent in stimulating gonadotropic hormone secretion via an action on the hypothalamic gonadotropin-releasing hormone (GnRH) neural system. Since the physiologic frequency of the GnRH pulse generator is a critical component of the control system that governs reproductive processes, the aim of this study was to examine the effect of kisspeptin-10 on pulsatile LH secretion and on the electrophysiological manifestation of GnRH pulse generator activity in order to determine frequency modulatory effects. Adult Sprague Dawley rats were ovariectomised and chronically implanted with electrodes in the arcuate nucleus to record the characteristic increases in hypothalamic multiunit electrical activity (MUA volleys) coincident with the initiation of each luteinizing hormone (LH) pulse measured in peripheral blood, and/or indwelling cardiac catheters for the collection of blood samples (25 microl) every 5 min for 6-7 h for the measurement of LH. Intravenous infusion of kisspeptin-10 (7.5, 35 and 100 nmol) induced a dose-dependent increase in LH secretion. The stimulatory effect of kisspeptin-10 (100nmol) on LH secretion was blocked by the GnRH antagonist Cetrorelix, precluding a singular action on gonadotropes. Unexpectedly, however, the marked increase in LH release in response to kisspeptin-10 (100 nmol) administration was not accompanied by any change in MUA volley frequency. It seem unlikely, therefore, that kisspeptin-10 has an appreciable frequency modulatory effect on GnRH pulse generator activity in the female rat. [Abstract/Link to Full Text]

Nüsken KD, Dötsch J, Rauh M, Rascher W, Schneider H
Uteroplacental insufficiency after bilateral uterine artery ligation in the rat: Impact on postnatal glucose and lipid metabolism and evidence for metabolic programming of the offspring by sham operation.
Endocrinology. 2007 Dec 6;
Ligation of the uterine arteries in rats (LIG) serves as a model of intrauterine growth restriction (IUGR) and subsequent developmental programming of impaired glucose tolerance, hyperinsulinemia and adiposity in the offspring. Its impact on lipid metabolism has been less well investigated. We compared parameters of glucose and lipid metabolism and glucocorticoid levels in the offspring of dams which underwent either LIG or sham operation (SOP) with those of untreated controls (C). Blood parameters including insulin, leptin and visfatin as well as body weight, food intake and creatinine clearance were recorded up to an age of 30 weeks, glucose tolerance tests were performed and both leptin and visfatin expression in liver, muscle, epididymal and mesenteric fat was quantified by RT-PCR. After catch-up growth, weight gain of all groups was similar, despite lower food intake of the LIG rats. LIG offspring showed impaired glucose tolerance from the age of 15 weeks as well as elevated glycosylated hemoglobin and corticosterone levels. However, the body fat content of both LIG and SOP animals increased relative to C, and both showed elevated triglyceride, total cholesterol and leptin levels as well as a reduced proportion of HDL cholesterol. Thus, use of the LIG model requires both SOP and C controls. While only LIG is associated with impaired glucose tolerance, pathogenic programming of the lipid metabolism can also be induced by SOP. Visfatin does not appear to be involved in the disturbed glucose metabolism following IUGR and may only represent a marker of fat accumulation. [Abstract/Link to Full Text]

Lichtenauer UD, Shapiro I, Geiger K, Quinkler M, Fassnacht M, Nitschke R, Rückauer KD, Beuschlein F
Side population does not define stem cell-like cancer cells in the adrenocortical carcinoma cell line NCI h295R.
Endocrinology. 2007 Dec 6;
Recent evidence suggests the existence of a stem cell-like subpopulation of cells in hematological and solid tumor entities, which determine the malignant phenotype of a given tumor through their proliferative potential and chemotherapy resistance. A recently utilized technique for the isolation of this cell population is through exclusion of the vital dye Hoechst 33342, which defines the so-called side population (SP). Herein we demonstrate the presence of SP cells in a variety of adrenal specimens, including primary cultures of human adrenocortical tumors and normal adrenal glands as well as established human and murine adrenocortical cancer cell lines by FACS analysis and confocal microscopy. On a functional level, SP cells from the human adrenocortical tumor cell line NCI h295R revealed an expression pattern consistent with a less differentiated phenotype, including lower expression of steroidogenic enzymes such as steroid acute regulatory protein (StAR) and side chain cleavage enzyme (P450scc) in comparison to non-SP cells. However, proliferation between SP and non-SP (NSP) cells did not differ (105.6+/-18.1% vs. 100.0+/-3.5%). Furthermore, re-sorting and tracing experiments revealed the capacity for both cell types to give rise to the original SP and non-SP containing cell population. Similarly to the baseline growth kinetics, no survival benefit was evident in SP cells after treatment with cytotoxic agents commonly used in adrenocortical carcinomas. Taken together, these findings provide evidence that Hoechst dye exclusion, in contrast to what has been reported for other tumor entities, is not a major tumor stem cell defining marker in adrenocortical NCI h295R tumor cells. [Abstract/Link to Full Text]

Tsao D, Thomsen HK, Chou J, Stratton J, Hagen M, Loo C, Garcia C, Sloane DL, Rosenthal A, Lin JC
TrkB Agonists Ameliorate Obesity and Associated Metabolic Conditions in Mice.
Endocrinology. 2007 Dec 6;
Mutations in the tyrosine kinase receptor trkB or in one of its natural ligands, brain-derived neurotrophic factor (BDNF), lead to severe hyperphagia and obesity in rodents and/or humans. Here, we show that peripheral administration of Neurotrophin-4 (NT4), the second natural ligand for trkB, suppresses appetite and body weight in a dose-dependent manner in several murine models of obesity. NT4 treatment increased lipolysis, reduced body fat content and leptin and elicited long lasting amelioration of hypertriglyceridemia and hyperglycemia. Following treatment termination, body weight gradually recovered to control levels in obese mice with functional leptin receptor. A single intrahypothalamic application of minute amounts of NT4 or an agonist trkB antibody also reduced food intake and body weight in mice. Taken together with the genetic evidence, our findings support the concept that trkB signaling which originates in the hypothalamus directly modulates appetite, metabolism and taste preference, downstream of the leptin and melanocortin 4 receptor (Mc4r). The trkB agonists mediate anorexic and weight reducing effects independent of stress induction, visceral discomfort or pain sensitization and thus emerge as a potential therapeutics for metabolic disorders. [Abstract/Link to Full Text]

Lai TH, Lin YF, Wu FC, Tsai YH
FSH-induced G{alpha}h/phospholipase C-{delta}1 signaling mediating a non-capacitative Ca2+-influx through T-type Ca2+-channels in rat Sertoli cells.
Endocrinology. 2007 Dec 6;
Our previous study demonstrated that follicle-stimulating hormone (FSH)-induced immediate Ca(2+)-influx in rat Sertoli cells (SCs) is mediated by Galphah/phospholipase C-delta1 (PLC-delta1) signaling pathway. As to which Ca(2+)-channel is responsible for such Ca(2+)-influx was not understood. In this study, thapsigargin triggered an in-stored calcium release, and evoked a 1.5-fold elevation of intracellular Ca(2+) in Ca(2+)-free media while FSH exhibited no effect. The re-addition of CaCl2 (2.5 mM) to FSH-pretreated or thapsigargin-sensitized SCs in Ca(2+)- free media immediately elicited a rapid Ca(2+)-influx or a 2-fold of second intracellular Ca(2+) elevation, respectively. The addition of Ca(2+) chelator, EGTA (0.2 mM), reduced the FSH-induced elevation of intracellular Ca(2+) in SCs incubated with CaCl2. However, the pretreatment with dantrolene (25 microM), which inhibits in-stored calcium release, did not affect the FSH-induced elevation of intracellular Ca(2+). NiCl2 (10 microM), a T-type calcium channel blocker, abolished the FSH-induced SC Ca(2+)-influx. Furthermore, mibefradil (10 and 100 microM), another specific blocker for T-type Ca(2+)-channels, dose-dependently suppressed the FSH-induced Ca(2+)-influx. In contrast, nifedipine (10 and 50 microM) or omega-conotoxin GVIA (100 and 500 nM), blocker of L- or N-type Ca(2+)-channels, respectively, did not affect the FSH-induced SC Ca(2+)-influx. On the other hand, FSH-induced Ca(2+)-influx was significantly reduced by the pretreatment of SCs with myristoylated synthetic peptide (0.1 and 1 microM) of PLC-delta1 fragment " TIPWNSLKQGYRHVHLL", but not interfered by 2',5'-dideoxyadenosine (3 and 15 microM), a selective inhibitor of adenylate cyclase. In conclusion, the FSH-induced Galphah/PLC-delta1 pathway-dependent Ca(2+)-influx of rat SCs is mediated by T-type Ca(2+)-channels and independent of instore-calcium release. [Abstract/Link to Full Text]

Peng J, Bencsik M, Louie A, Lu W, Millard S, Nguyen P, Burghardt A, Majumdar S, Wronski TJ, Halloran B, Conklin BR, Nissenson RA
Conditional Expression of a Gi-coupled Receptor in Osteoblasts Results in Trabecular Osteopenia.
Endocrinology. 2007 Nov 29;
G protein-coupled receptors (GPCRs) coupled to activation of Gs, such as the PTH1 receptor (PTH1R), have long been known to regulate skeletal function and homeostasis. However, the role of GPCRs coupled to other G proteins such as Gi is not well established. We used the tet-off system to regulate the expression of an activated Gi-coupled GPCR ("Ro1") in osteoblasts in vivo. Skeletal phenotypes were assessed in mice expressing Ro1 from conception, from late stages of embryogenesis, and post-weaning. Long bones were assessed histologically and by micro-CT. Expression of Ro1 from conception resulted in neonatal lethality that was associated with reduced bone mineralization. Expression of Ro1 starting at late embryogenesis resulted in a severe trabecular bone deficit at 12 weeks of age (> 51% reduction in BV/TV in the proximal tibia compared to sex-matched control littermates; n = 11, p< 0.01). Ro1 expression for 8 weeks beginning at 4 weeks of age resulted in a > 20% reduction in trabecular BV/TV compared to sex-matched control littermates (n = 16, p < 0.01). Bone histomorphometry revealed that Ro1 expression is associated with reduced rates of bone formation and mineral apposition without a significant change in osteoblast or osteoclast surface. Our results indicate that signaling by a Gi-coupled GPCR in osteoblasts leads to osteopenia resulting from a reduction in trabecular bone formation. The severity of the phenotype is related to the timing and duration of Ro1 expression during growth and development. The skeletal phenotype in Ro1 mice bears some similarity to that produced by knockout of Gs-alpha expression in osteoblasts, and thus may be due at least in part to Gi-mediated inhibition of adenylyl cyclase. [Abstract/Link to Full Text]

Meziani F, Tesse A, Welsch S, Kremer H, Barthelmebs M, Andriantsitohaina R, Schneider F, Gairard A
Expression and biological activity of Parathyroid Hormone-Related Peptide (PTHrP) in pregnant rat uterine artery: Any role for 8 iso Prostaglandin F2{alpha}?
Endocrinology. 2007 Nov 29;
PTHrP is produced in vessels and acts as a local modulator of tone. We recently reported that PTHrP(1-34) is able to induce vasorelaxation in rat uterine arteries but, in pregnancy, this response is blunted and becomes strictly endothelium-dependent. The present study aimed to get insights into the mechanisms involved in these changes because the adaptation of uterine blood flow is essential for fetal development. On day 20 of gestation RT-PCR analysis of uterine arteries showed that PTH/PTHrP receptor (PTH1R) mRNA expression was decreased whereas that of PTHrP mRNA was increased. This was associated with a redistribution of the PTHrP/PTH1R system, with both PTH1R protein and PTHrP peptide becoming concentrated in the intimal layer of arteries from pregnant rats. On the other hand, the blunted vasorelaxation induced by PTHrP(1-34) in uterine arteries from pregnant rats was specifically restored by indomethacin and a specific cyclooxygenase-2 (COX-2) inhibitor, NS 398. This was associated with an increase in COX-2 expression and in 8-iso Prostaglandin F2alpha release when uterine arteries from pregnant rats were exposed to high levels of PTHrP(1-34). Most interestingly, 8-iso Prostaglandin F2alpha itselfwas able to increase PTHrP expression and reduce PTH1R expression in cultured rat aortic smooth muscle cells. These results suggest a local regulation of uterine artery functions by PTHrP during pregnancy resulting from PTH1R redistribution. Moreover, they shed light on a potential role of 8-iso Prostaglandin F2alpha. [Abstract/Link to Full Text]

Bukulmez O, Hardy DB, Carr BR, Word RA, Mendelson CR
INFLAMMATORY STATUS INFLUENCES AROMATASE AND STEROID RECEPTOR EXPRESSION IN ENDOMETRIOSIS.
Endocrinology. 2007 Nov 29;
Aberrant upregulation of aromatase in eutopic endometrium and implants from women with endometriosis has been reported. Aromatase induction may be mediated by increased cyclooxygenase-2 (COX-2). Recently, we demonstrated that progesterone receptor (PR)-A and PR-B serve an anti-inflammatory role in uterus by antagonizing nuclear factor kappaB activation and COX-2 expression. PR-C, which antagonizes PR-B, is upregulated by inflammation. While estrogen receptor alpha (ERalpha) is implicated in endometriosis, an anti-inflammatory role of ERbeta has been suggested. We examined stage-specific expression of aromatase, COX-2, ER and PR isoform expression in eutopic endometrium, implants, peritoneum and endometrioma samples from endometriosis patients. Endometrial and peritoneal biopsies were obtained from unaffected women and those with fibroids. Aromatase expression in eutopic endometrium from endometriosis patients was significantly increased compared to controls. Aromatase expression in endometriosis implants was markedly increased compared to eutopic endometrium. Aromatase mRNA levels were increased significantly in 'red' implants relative to 'black' implants and endometrioma cyst capsule. Moreover, COX-2 expression was increased in implants and in eutopic endometrium of women with endometriosis, as compared to control endometrium. As observed for aromatase mRNA, highest levels of COX-2 mRNA were found in red implants. The ratio of ERbeta/ERalpha mRNA was significantly elevated in endometriomas compared to endometriosis implants and eutopic endometrium. Expression of PR-C mRNA relative to PR-A and PR-B mRNA was significantly increased in endometriomas compared to eutopic and control endometrium. PR-A protein was barely detectable in endometriomas. Thus, whereas, PR-C may enhance disease progression, upregulation of ERbeta may play an anti-inflammatory and opposing role. [Abstract/Link to Full Text]

Lee TM, Lin MS, Chang NC
Physiological concentration of 17{beta}-Estradiol on Sympathetic Reinnervation in Ovariectomized Infarcted Rats.
Endocrinology. 2007 Nov 29;
17beta-estradiol (E2) has been shown to exert antiarrhythmic effect after myocardial infarction; however, the mechanisms remain unclear. This study was performed to determine whether E2 exerts beneficial effects through attenuated sympathetic hyperreinnervation after infarction. Two weeks after ovariectomy, female Wistar rats were assigned to coronary artery ligation or sham-operation. Twenty-four hours after coronary ligation, rats underwent one of five treatments: 1) subcutaneous vehicle treatment (control), 2) subcutaneous E2 treatment, 3) subcutaneous E2 treatment + tamoxifen (a potent estrogen receptor antagonist), 4) bosentan (an endothelin receptor blocker), or 5) subcutaneous E2 treatment + bosentan and followed for 4 weeks. Myocardial endothelin-1 and norepinephrine levels at the remote zone revealed a significant elevation in control infarcted rats compared with sham-operated rats, which is consistent with sympathetic hyperinnervation after infarction. Sympathetic hyperinnervation was blunted after giving the rats either E2 or bosentan, assessed by immunohistochemical analysis of tyrosine hydroxylase, growth associated protein 43 and neurofilament, and Western blotting and real-time quantitative RT-PCR of nerve growth factor. Arrhythmic scores during programmed stimulation in E2-treated infarcted rats were significantly lower than in control infarcted rats. Addition of bosentan did not have additional beneficial effects compared with rats treated with E2 alone. The beneficial effect of E2 on sympathetic hyperinnervation was abolished by tamoxifen. Our data indicated that E2 has a role for sympathetic hyperinnervation after infarction probably through an endothelin-1-depedent pathway. Chronic administration of E2 after infarction may attenuate the arrhythmogenic response to programmed electrical stimulation. [Abstract/Link to Full Text]

Leranth C, Szigeti-Buck K, Maclusky NJ, Hajszan T
Bisphenol A Prevents the Synaptogenic Response to Testosterone in the Brain of Adult Male Rats.
Endocrinology. 2007 Nov 29;
Exposure measurement data from several developed countries indicate that human beings are widely exposed to low levels of the synthetic xenoestrogen, bisphenol A. We have reported previously that bisphenol A even at doses below the reference safe daily limit for human exposure, recommended by the U.S. Environmental Protection Agency, impairs the synaptogenic response to 17beta-estradiol in the hippocampus of ovariectomized rats. Recent experiments have revealed that bisphenol A also interferes with androgen receptor-mediated transcriptional activities. Thus, to investigate whether bisphenol A impairs synaptogenesis in the medial prefrontal cortex (mPFC) and hippocampus of adult male rats, castrated and sham-operated animals were treated with different combinations of bisphenol A (300 microg/kg), testosterone propionate (1.5 mg/kg), and sesame oil vehicle. The brains were processed for electron microscopic stereology, and the number of asymmetric spine synapses in the mPFC and CA1 hippocampal area was estimated. In both regions analyzed, bisphenol A reduced the number of spine synapses in sham-operated, gonadally intact animals, which was accompanied by a compensatory increase in astroglia process density. In addition, bisphenol A prevented both the prefrontal and hippocampal synaptogenic response to testosterone supplementation in castrated males. These results demonstrate that bisphenol A interferes with the synaptogenic response to testosterone in the mPFC and hippocampus of adult male rats. Because the hippocampal synaptogenic action of androgens seems to be independent of androgen and estrogen receptors in males, the potential mechanisms that underlie these negative effects of bisphenol A remain the subject of further investigation. [Abstract/Link to Full Text]

Chen J, Ahn KC, Gee NA, Mohamed MI, Duleba AJ, Zhao L, Gee SJ, Hammock BD, Lasley BL
Triclocarban enhances testosterone action: A new type of endocrine disruptor?
Endocrinology. 2007 Nov 29;
Many xenobiotics have been associated with endocrine effects in a wide range of biological systems. These associations are usually between small non-steroid molecules and steroid receptor signaling systems. In this report, triclocarban (TCC; 3,4,4'-trichlorocarbanilide), a common ingredient in personal care products that is employed as an antimicrobial agent was evaluated and found to represent a new category of endocrine-disrupting substance (EDS). A cell-based androgen receptor-mediated bioassay was used to demonstrate that TCC and other urea compounds with a similar structure, which have little or no endocrine activity when tested alone, act to enhance testosterone (T) induced androgen receptor-mediated transcriptional activity in vitro. This amplification effect of TCC was also apparent in vivo when 0.25% TCC was added to the diet of castrated male rats that were supported by exogenous testosterone treatment for ten days. All male sex accessory organs increased significantly in size following the T+TCC treatment compared to T or TCC treatments alone. The data presented here suggest that the bioactivity of endogenous hormones may be amplified by exposure to commercial personal care products containing sufficient levels of TCC. [Abstract/Link to Full Text]

Kohno D, Nakata M, Maejima Y, Shimizu H, Sedbazar U, Yoshida N, Dezaki K, Onaka T, Mori M, Yada T
Nesfatin-1 neurons in paraventricular and supraoptic nuclei of the rat hypothalamus coexpress oxytocin and vasopressin and are activated by refeeding.
Endocrinology. 2007 Nov 29;
Nesfatin-1, a newly discovered satiety molecule, is located in the hypothalamic nuclei, including the paraventricular nucleus (PVN) and supraoptic nucleus (SON). In this study, fine localization and regulation of nesfatin-1 neurons in the PVN and SON were investigated by immunohistochemistry of neuropeptides and c-Fos. In the PVN, 24% of nesfatin-1 neurons overlapped with oxytocin, 18% with vasopressin, 13% with CRH, and 12% with TRH neurons. In the SON, 35% of nesfatin-1 neurons overlapped with oxytocin, and 28% with vasopressin. Following a 48 hour fast, refeeding for 2 hours dramatically increased the number of nesfatin-1 neurons expressing c-Fos immunoreactivity in the PVN approximately by 10 times and in the SON by 30 times compared to the fasting controls. In the SON, refeeding also significantly increased the number of nesfatin-1-immunoreactive neurons and NUCB2 mRNA expression, as compared to fasting. These results indicate that nesfatin-1 neurons in the PVN and SON highly overlap with oxytocin and vasopressin neurons, and that they are activated markedly by refeeding. Feeding-activated nesfatin-1 neurons in the PVN and SON could play a role in the postprandial regulation of feeding behavior and energy homeostasis. [Abstract/Link to Full Text]

Popovici RM, Krause MS, Jauckus J, Germeyer A, Brum IS, Garlanda C, Strowitzki T, von Wolff M
The Long Pentraxin PTX3 in Human Endometrium: Regulation by Steroids and Trophoblast Products.
Endocrinology. 2007 Nov 29;
Human implantation is characterized by blastocyst attachment to endometrial epithelial cells followed by invasion of trophoblast into the maternal decidua. There has been an increasing amount of data linking higher levels of PTX3, a long pentraxin, to embryo implantation. PTX3 levels were found to be higher in patients with preeclampsia and intrauterine growth restriction (IUGR), both conditions caused by faulty implantation. Furthermore, PTX3 knock-out mice have reduced fertility due to cumulus oopherus malformation as well as implantation failure. In a human implantation model we and others have shown that trophoblast action on endometrial stromal cells induces PTX3 expression. In this study, we analyze PTX3 expression throughout the menstrual cycle as well as its regulation by hormones involved in the implantation process. We also compared PTX3 expression in stromal cells induced by trophoblast conditioned medium to its induction by trophoblast co-culture. PTX3 mRNA expression in human endometrial stromal cells is regulated by progesterone, estrogen and IL-1, but not by HCG and is increased by both trophoblast conditioned medium as well as by trophoblast explants. PTX3 protein production and regulation by these factors is shown by Western Blot. Based on these findings, we conclude that estradiol and progesterone are involved in PTX3 induction and regulation during implantation. Also, of the factors secreted by trophoblast, IL1beta induces PTX3 in human endometrial stromal cells. [Abstract/Link to Full Text]

Rumball CW, Oliver MH, Thorstensen EB, Jaquiery AL, Husted SM, Harding JE, Bloomfield FH
Effects of twinning and periconceptional undernutrition on late-gestation hypothalamic-pituitary-adrenal axis function in ovine pregnancy.
Endocrinology. 2007 Nov 29;
The relationships between reduced size at birth, increased activity of the hypothalamic-pituitary-adrenal (HPA) axis and increased risk of disease in adulthood are well described in singletons, but are much less clear in twins. This may be because the physiological processes underlying reduced size at birth are different in singletons and twins. Periconceptional undernutrition can cause altered activity of the fetal and postnatal HPA axis without altering size at birth. However, the independent effects of periconceptional undernutrition and twinning on activity of the maternal and fetal HPA axes are not well described. We therefore studied maternal and fetal HPA axis function during late gestation in twin and singleton sheep pregnancies, either undernourished around conception or fed ad libitum. We found that twinning led to suppressed baseline HPA axis function and decreased adrenal sensitivity to ACTH stimulation, but increased fetal pituitary ACTH response both to direct stimulation by corticotropin-releasing hormone (ACTH area under the curve response: 29.7+/-2.2 vs 17.1+/-1.6 ng.min.mL(-1), p<0.01), and to decreased cortisol negative feedback. In contrast, periconceptional undernutrition resulted in a decreased pituitary response (ACTH area under the curve response: 19.4+/-1.6 vs 26.1+/-2.2 ng.min.mL(-1), p=0.02), but no difference in adrenal response. Thus, the HPA axis function of twin sheep fetuses in late gestation is very different from that of control and undernourished singletons. If the HPA axis is an important mediator between fetal adaptations and adult disease, these data may help explain why the relationship between fetal growth and postnatal physiology and disease risk is inconsistent in twins. [Abstract/Link to Full Text]

Metlakunta AS, Sahu M, Sahu A
Hypothalamic Phosphatidylinositol 3-kinase pathway of leptin signaling is impaired during the development of diet-induced obesity in FVB/N mice.
Endocrinology. 2007 Nov 29;
Phosphatidylinositol 3-kinase (PI3K) pathway of leptin signaling plays an important role in transducing leptin action in the hypothalamus. Obesity is usually associated with resistance to the effect of leptin on food intake and energy homeostasis. Although central leptin resistance is thought to be involved in the development of diet-induced obesity (DIO), mechanism behind this phenomenon is not clearly understood. To determine whether DIO impairs the effect of leptin on hypothalamic PI3K signaling, we fed four weeks old FVB/N mice a high-fat diet (HFD) or low-fat diet (LFD) for 19 weeks. HFD fed mice developed DIO in association with hyperleptinemia, hyperinsulinemia and impaired glucose and insulin tolerance. Leptin (i.p.) significantly increased hypothalamic PI3K activity and p-STAT3 (signal transducer and activator of transcription-3) levels in LFD-fed mice but not in DIO mice. Immunocytochemical (ICC) study confirmed impaired p-STAT3 activation in various hypothalamic areas including the arcuate nucleus. We next tested whether both PI3K and STAT3 pathways of leptin signaling were impaired during the early period of DIO. Leptin failed to increase PI3K activity in DIO mice that were on HFD for 4 weeks. However, leptin-induced p-STAT3 activation in the hypothalamus measured by Western blotting and ICC remained comparable between LFD- and HFD-fed mice. These results suggest that PI3K pathway but not the STAT3 pathway of leptin signaling is impaired during the development of DIO in FVB/N mice. Thus, defective PI3K pathway of leptin signaling in the hypothalamus may be one of the mechanisms of central leptin resistance and DIO. [Abstract/Link to Full Text]

Kiefer FW, Zeyda M, Todoric J, Huber J, Geyeregger R, Weichhart T, Aszmann O, Ludvik B, Silberhumer GR, Prager G, Stulnig TM
Osteopontin expression in human and murine obesity: extensive local upregulation in adipose tissue but minimal systemic alterations.
Endocrinology. 2007 Nov 29;
Obesity is associated with a chronic low grade inflammation characterized by macrophage infiltration of adipose tissue (AT) that may underlie development of insulin resistance and type 2 diabetes. Osteopontin (OPN) is a multifunctional protein involved in various inflammatory processes, cell migration, and tissue remodeling. Since these processes occur in AT of obese patients, we studied in detail the regulation of OPN expression in human and murine obesity. The study included 20 morbidly obese patients and 20 age- and sex-matched control subjects, as well as two models (diet-induced and genetic) of murine obesity. In high-fat diet-induced and genetically obese mice, OPN expression was drastically upregulated in AT (40 and 80-fold, respectively), but remained largely unaltered in liver (< 2-fold). Moreover, OPN plasma concentrations remained unchanged in both murine models of obesity, suggesting a particular local but not systemic importance for OPN. OPN expression was strongly elevated also in AT of obese patients compared to lean subjects in both omental and subcutaneous AT. In addition, we detected three OPN isoforms to be expressed in human AT and, strikingly, an obesity-induced alteration of the OPN isoform expression pattern. Analysis of AT cellular fractions revealed that OPN is exceptionally highly expressed in AT macrophages (ATMs) in humans and mice. Moreover, OPN expression in ATMs was strongly upregulated by obesity. In conclusion, our data point towards a specific local role of OPN in obese AT. Hence, OPN could be a critical regulator in obesity-induced AT inflammation and insulin resistance. [Abstract/Link to Full Text]

Gomez-Sanchez EP, Romero DG, de Rodriguez AF, Warden MP, Krozowski Z, Gomez-Sanchez CE
Hexose-6-Phosphate Dehydrogenase and 11 beta-Hydroxysteroid Dehydrogenase-1 Tissue Distribution in the Rat.
Endocrinology. 2007 Nov 26;
Intracellular concentrations of the glucocorticoids cortisol and corticosterone are modulated by the enzymes 11ss-hydroxysteroid dehydrogenase 1 and 2 (11ssHSD1 and 11ssHSD2). 11ssHSD1 is an NADPH-dependent microsomal reductase that converts the inactive glucocorticoids cortisone and 11-dehydrocorticosterone to their active forms, cortisol and corticosterone. Hexose-6-phosphate dehydrogenase (H6PDH) is an enzyme that generates NADPH from NADP(+) within the endoplasmic reticulum. In the absence of NADPH or H6PDH to regenerate NADPH, 11ssHSD1 acts as a dehydrogenase and inactivates glucocorticoids, as does 11ssHSD2. A monoclonal antibody against H6PDH was produced to study the possibility that 11ss -HSD1 in the absence of H6PDH may be responsible for hydroxysteroid dehydrogenase activity in tissues that do not express significant amounts of 11ssHSD2. H6PDH and 11ssHSD1 expression was surveyed in a variety of rat tissues by real time RT-PCR, western blot analysis and immunohistochemistry. H6PDH was found in a wide variety of tissues with the greatest concentrations in the liver, kidney and leydig cells. While the brain as a whole did not express significant amounts of H6PDH, some neurons were clearly immunoreactive by immunohistochemistry. H6PDH was amply expressed in most tissues examined in which 11ssHSD1 was also expressed, with the notable exception of the renal interstitial cells, where dehydrogenase activity by 11ssHSD1 probably moderates activation of the glucocorticoid receptor, as rat renal interstitial cells do not have significant amounts of mineralocorticoid receptors. This antibody against the H6PDH should prove useful for further studies of enzyme activity requiring NADPH generation within the endoplasmic reticulum. [Abstract/Link to Full Text]

Bayo P, Sanchis A, Bravo A, Cascallana JL, Buder K, Tuckermann J, Schütz G, Pérez P
Glucocorticoid receptor is required for skin barrier competence.
Endocrinology. 2007 Nov 26;
To investigate the contribution of the glucocorticoid receptor (GR) in skin development and the mechanisms underlying this function, we have analyzed two mouse models in which GR has been functionally inactivated: the knock-out GR(-/-) mice and the dimerization mutant GR(dim/dim) that mediates defective DNA binding-dependent transcription. Since GR null mice die perinatally, we evaluated skin architecture of late embryos by histological, immunohistochemical and electron microscopy studies. Loss-of-function of GR resulted in incomplete epidermal stratification with dramatically abnormal differentiation of GR(-/-), but not GR(+/-) embryos, as demonstrated by the lack of loricrin, filaggrin and involucrin markers. Skin sections of GR(-/-) embryos revealed edematous basal and lower spinous cells and electron micrographs showed increased intercellular spaces between keratinocytes and reduced number of desmosomes. The absent terminal differentiation in GR(-/-) embryos correlated with an impaired activation of caspase-14, which is required for the processing of profilaggrin into filaggrin at late embryo stages. Accordingly, the skin barrier competence was severely compromised in GR(-/-) embryos. Cultured mouse primary keratinocytes (MPK) from GR(-/-) mice formed colonies with cells of heterogeneous size and morphology that showed increased growth and apoptosis, indicating that GR regulates these processes in a cell-autonomous manner. The activity of ERK1/2 was constitutively augmented in GR(-/-) skin and MPKs relative to wt, which suggests that GR modulates skin homeostasis, at least partially, by antagonizing ERK function. Moreover, the epidermis of GR(+/dim) and GR(dim/dim) embryos appeared normal, thus suggesting that DNA-binding-independent actions of GR are sufficient to mediate epidermal and hair follicle development during embryogenesis. [Abstract/Link to Full Text]

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Recent Articles in Molecular Endocrinology

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Fretz JA, Shevde NK, Singh S, Darnay BG, Pike JW
RANKL-INDUCED NUCLEAR FACTOR OF ACTIVATED T CELLS (C1) AUTOREGULATES ITS OWN EXPRESSION IN OSTEOCLASTS AND MEDIATES THE UPREGULATION OF TARTRATE-RESISTANT ACID PHOSPHATASE.
Mol Endocrinol. 2007 Dec 6; .
Osteoclasts are large multinucleated, bone resorbing cells derived from hematopoietic precursors in response to RANKL. RANKL activates a number of signal transduction pathways which stimulate in turn a series of specific transcription factors that initiate the process of osteoclastogenesis. Perhaps the most important of these is NFATc1, a DNA binding protein that upon activation translocates to the nucleus where it stimulates transcription. The objective of this study was to explore the process whereby RANKL induces NFATc1 and to assess the role of this factor in the activation of an additional key osteoclast target gene. We found that while several NFAT members are expressed in RAW264.7 cells, sRANKL-induced upregulation is limited to NFATc1 through a mechanism that is largely autoregulatory. Thus, while we observed the presence of resident NFAT members at the inducible Nfatc1 P1 promoter at very early times following RANKL treatment, a selective and time-dependent increase in the binding of upregulated NFATc1 to Nfatc1 was observed beginning at 12 hr. Several additional factors that are activated by sRANKL and also participate in NFATc1 upregulation include c-fos and RNA polymerase II. ChIP analysis also revealed a similar, time-dependent accumulation of NFATc1 at multiple sites on the Acp5 promoter, thereby highlighting a central contributing role for NFATc1 in the activation of this gene as well. Our studies provide additional molecular detail regarding the mechanisms through which RANKL induces NFATc1 in osteoclast precursors and into mechanisms by which NFATc1-induces the expression of at least one gene responsible for the osteoclast phenotype. [Abstract/Link to Full Text]

Tremblay AM, Wilson BJ, Yang XJ, Giguère V
Phosphorylation-Dependent Sumoylation Regulates ERR{alpha} and {gamma} Transcriptional Activity Through a Synergy Control Motif.
Mol Endocrinol. 2007 Dec 6;
Interplay between different post-translational modifications of transcription factors is an important mechanism to achieve an integrated regulation of gene expression. For the estrogen-related receptors (ERR) alpha and gamma, regulation by post-translational modifications is still poorly documented. Here we show that transcriptional repression associated with the ERR amino-terminal domains is mediated through sumoylation at a conserved phospho-sumoyl switch, psiKxEPxSP, that exists within a larger synergy control motif. Arginine substitution of the sumoylatable lysine residue or alanine substitution of a nearby phosphorylatable serine residue (serine 19 in ERRalpha) increased the transcriptional activity of both ERRalpha and gamma. In addition, phospho-mimetic substitution of the serine residue with aspartate restored the sumoylation and transcriptional repression activity. The increased transcriptional activity of the sumoylation-deficient mutants was more pronounced in the presence of multiple adjacent ERR response elements. We also identified PIASy [protein inhibitor activated STAT (signal transducer and activator of transcription) y] as an interacting partner and a SUMO E3 ligase for ERRalpha. Importantly, analysis with a phosphospecific antibody revealed that sumoylation of ERRalpha in mouse liver requires phosphorylation of serine 19. Taken together, these results show that the interplay of phosphorylation and sumoylation in the amino-terminal domain provides an additional mechanism to regulate the transcriptional activity of ERRalpha and gamma. [Abstract/Link to Full Text]

Wang C, Dehghani B, Magrisso IJ, Rick EA, Bonhomme E, Cody DB, Elenich LA, Subramanian S, Murphy SJ, Kelly MJ, Rosenbaum JS, Vandenbark AA, Offner H
GPR30 Contributes to Estrogen-Induced Thymic Atrophy.
Mol Endocrinol. 2007 Dec 6;
The mechanisms by which prolonged estrogen exposures, such as estrogen therapy and pregnancy, reduce thymus weight, cellularity, and CD4 and CD8 phenotype expression, have not been well defined. In this study, the roles played by the membrane estrogen receptor, G protein-coupled receptor 30 (GPR30), and the intracellular estrogen receptors, estrogen receptor . (ERalpha) and beta (ERbeta), in 17beta-estradiol (E2)-induced thymic atrophy were distinguished by construction and the side-by-side comparison of GPR30-deficient (GPR30KO) mice with ERalpha (AERKO) and ERbeta (BERKO) gene-deficient mice. Our study shows that while ERalpha mediated exclusively the early developmental blockage of thymocytes, GPR30 was indispensable for thymocyte apoptosis that preferentially occurs in TCRbeta(-/low) DP thymocytes. Additionally, G1, a specific GPR30 agonist, induces thymic atrophy and thymocyte apoptosis, but not developmental blockage. Finally, E2-treatment attenuates the activation of NFkappaB in CD25(-)CD4(-)CD8(-) double negative (DN) thymocytes through an ERalpha . -dependent yet ERbeta- and GPR30-independent pathway. Differential inhibition of NFkappaB by ERalpha and GPR30 might underlie their disparate physiological effects on thymocytes. Our study distinguishes for the first time the respective contributions of nuclear and membrane E2 receptors in negative regulation of thymic development. [Abstract/Link to Full Text]

Mattingly KA, Ivanova MM, Riggs KA, Wickramasinghe NS, Barch MJ, Klinge CM
Estradiol stimulates transcription of Nuclear Respiratory Factor-1 and increases mitochondrial biogenesis.
Mol Endocrinol. 2007 Nov 29;
Estrogen has direct and indirect effects on mitochondrial activity, but the mechanisms mediating these effects remain unclear. Others reported that long term estradiol (E2) treatment increased Nuclear Respiratory Factor-1 (NRF-1) protein in cerebral blood vessels of ovariectomized rats. NRF-1 is a transcription factor that regulates the expression of nuclear-encoded mitochondrial genes, e.g., mitochondrial transcription factor A (TFAM), that control transcription of the mitochondrial genome. Here we tested the hypothesis that E2 increases NRF-1 transcription resulting in a coordinate increase in the expression of nuclear- and mitochondrial- encoded genes and mitochondrial respiratory activity. We show that E2 increased NRF-1 mRNA and protein in MCF-7 breast and H1793 lung adenocarcinoma cells in a time-dependent manner. E2-induced NRF-1 expression was inhibited by the estrogen receptor (ER) antagonist ICI 182,780 and Actinomycin D, but not by phosphoinositide-3 kinase and MAPK inhibitors, indicating a genomic mechanism of E2 regulation of NRF-1 transcription. An estrogen response element (ERE) in the NRF-1 promoter bound ERalpha and ERbeta in vitro and E2 induced ERalpha and ERbeta recruitment to this ERE in chromatin immunoprecipitation assays in MCF-7 cells. The NRF-1 ERE activated reporter gene expression in transfected cells. siRNA to ERalpha and ERbeta revealed that ERalpha mediates E2-induced NRF-1 transcription. The E2-induced increase in NRF-1 was followed by increased TFAM and the transcription of Tfam-regulated mtDNA-encoded COI and NDI genes and increased mitochondrial biogenesis. Knockdown of NRF-1 blocked E2-stimulation of mitochondrial biogenesis and activity indicating a mechanism by which estrogens regulate mitochondrial function by increasing NRF-1 expression. [Abstract/Link to Full Text]

Markovic D, Punn A, Lehnert H, Grammatopoulos DK
INTRACELLULAR MECHANISMS REGULATING CRH-R2{beta}-ENDOCYTOSIS AND INTERACTION WITH ERK1/2 AND P38MAPK SIGNALING CASCADES.
Mol Endocrinol. 2007 Nov 29;
Many important physiological roles of the urocortin (UCN)-family of peptides as well as corticotropin-releasing hormone (CRH), involve the type 2 CRH receptor (CRH-R2) and downstream activation of multiple pathways. To characterize molecular determinants of CRH-R2 functional activity, we used HEK293 cells overexpressing recombinant CRH-R2beta and investigated mechanisms involved in attenuation of CRH-R2 signaling activity and uncoupling from intracellular effectors. CRH-R2beta-mediated adenylyl cyclase activation was sensitive to homologous desensitization induced by pretreatment with either UCN-II or the weaker agonist CRH. CRH-R2beta activation induced transient beta-arrestin1 and beta-arrestin2, as well as clathrin, recruitment to the plasma membrane. beta-Arrestin2 appeared to be the main beta-arrestin subtype associated with the receptor. This was followed by CRH-R2beta endocytosis in a mechanism that exhibited distinct agonist-dependent temporal characteristics. CRH-R2beta also induced transient activation of the ERK1/2 and p38MAPK signaling cascades that peaked at 5min and returned to basal within 20-30min. Unlike p38MAPK, activated ERK1/2 was localized both in the cytoplasm and nucleus. Experiments employing inhibitors of receptor endocytosis showed that CRH-R2beta-MAPK interaction does not require beta-arrestin, clathrin or receptor endocytosis. Site-directed mutagenesis studies on CRH-R2beta C-terminus showed that the aminoacid cassette TAAV at the end of the C-terminus is important for CRH-R2beta signaling since loss of a potential phospho-acceptor site in mutant receptors containing deletion or Ala substitution of the cassette TAAV resulted in reduced ERK1/2 activation and accelerated receptor internalization. These findings provide new insights about the signaling mechanisms regulating CRH-R2beta functional activity and determining its biological responses. [Abstract/Link to Full Text]

Rantakari P, Strauss L, Kiviranta R, Lagerbohm H, Paviala J, Holopainen I, Vainio S, Pakarinen P, Poutanen M
Placenta Defects and Embryonic Lethality Resulting from Disruption of Mouse Hydroxysteroid (17-beta) Dehydrogenase 2 Gene.
Mol Endocrinol. 2007 Nov 29;
Hydroxysteroid (17-beta) dehydrogenase 2 (HSD17B2) is a member of aldo-keto reductase superfamily, known to catalyze the inactivation of 17beta-hydroxysteroids to less active 17-keto forms, and catalyze the conversion of 20alpha-hydroxyprogesterone to progesterone in vitro. To examine the role of HSD17B2 in vivo, we generated mice deficient in Hsd17b2 (HSD17B2KO) by a targeted gene disruption in embryonic stem cells. From the homozygous mice carrying the disrupted Hsd17b2, 70% showed embryonic lethality appearing at the age of E11.5 onwards. The embryonic lethality was associated with reduced placental size measured at the E17.5. The HSD17B2KO mice placentas presented with structural abnormalities in all tree major layers; the decidua, spongiotrophoblast and labyrinth. Most notable was the disruption of the spongiotrophoblast and labyrinthine layers, together with liquid filled cysts in the junctional region and the basal layer. Treatments with an antiestrogen or progesterone did not rescue the embryonic lethality or the placenta defect in the homozygous mice. In hybrid backround used, 24% of HSD17B2KO mice survived through fetal period but were born growth retarded and displayed a phenotype in the brain with enlargement of ventricles, abnormal laminar organization and increased cellular density in the cortex. Furthermore, the HSD17B2KO mice had unilateral renal degeneration, the affected kidney frequently appearing as a fluid filled sac. Our results provide evidence for a role for HSD17B2 enzyme in the cellular organization of the mouse placenta. [Abstract/Link to Full Text]

Eacker SM, Agrawal N, Qian K, Dichek HL, Gong EY, Lee K, Braun RE
Hormonal Regulation of Testicular Steroid and Cholesterol Homeostasis.
Mol Endocrinol. 2007 Nov 21;
The male sex steroid, testosterone (T), is synthesized from cholesterol in the testicular Leydig cell under control of the pituitary gonadotropin luteinizing hormone (LH). Unlike most cells that utilize cholesterol primarily for membrane synthesis, steroidogenic cells have additional requirements for cholesterol, as it is the essential precursor for all steroid hormones. Little is known about how Leydig cells satisfy their specialized cholesterol requirements for steroid synthesis. We show that in mice with a unique hypomorphic androgen mutation, which disrupts the feedback loop governing T synthesis, that genes involved in cholesterol biosynthesis/uptake and steroid biosynthesis are upregulated. We identify LH as the central regulatory molecule that controls both steroidogenesis and Leydig cell cholesterol homeostasis in vivo. In addition to the primary defect caused by high levels of LH, absence of T-signaling exacerbates the lipid homeostasis defect in Leydig cells by eliminating a short feedback loop. We show T-signaling can affect the synthesis of steroids and modulates the expression of genes involved in de novo cholesterol synthesis. Surprisingly, accumulation of active SREBP2 is not required for up-regulation of genes involved in cholesterol biosynthesis and uptake in Leydig cells. [Abstract/Link to Full Text]

Kabir-Salmani M, Fukuda MN, Kanai-Azuma M, Ahmed N, Shiokawa S, Akimoto Y, Sakai K, Nagamori S, Kanai Y, Sugihara K, Iwashita M
The Membrane-Spanning Domain of CD98hc Promotes {alpha}v{beta}3 Integrin Signals in Human Extravillous Trophoblasts.
Mol Endocrinol. 2007 Nov 21;
CD98 heavy chain (CD98hc) is expressed highly in developing human placental trophoblast. CD98hc is an amino acid transporter, and is thought to function in cell fusion, adhesion and invasion by interacting with integrins. In invasive extravillous trophoblast, alphavbeta3 integrin is expressed in temporally and spatially specific manner, which prompted us to investigate the potential role of CD98hc in signal transduction of alphavbeta3 integrin. Immunocytochemistry of extravillous trophoblast derived from human placenta revealed that CD98hc co-localized with alphavbeta3 integrin, and with alphavbeta3-associated cytoplasmic proteins including paxillin, vinculin and FAK. Co-immunoprecipitation of CD98hc and its mutants revealed that the transmembrane domain of CD98hc is necessary for the association of CD98hc with alphavbeta3 integrin. When CD98hc negative liver cells (FLC4) were stably transfected with CD98hc and the extracellular domain of CD98hc was cross-linked by anti-CD98 antibody, FLC4 cells binding affinity to fibronectin and cell motility increased. The anti-CD98 antibody cross-linking promoted actin stress fiber formation and activation of signal transduction downstream of RhoA GTPase, and elevated the phosphorylation of FAK, paxillin, and protein kinase B (AKT). Pretreatment of transfected FLC4 cells with specific inhibitors for alphavbeta3integrin, phosphoinositol 3-OH kinase (PI3-K) and RhoA diminished these effects caused by anti-CD98 antibody cross-linking. These results suggest that notoriously invasive activity of extravillous trophoblast is mediated by CD98hc, which promotes alphavbeta3integrin-dependent signals. [Abstract/Link to Full Text]

Zaninetti R, Tacchi S, Erriquez J, Distasi C, Maggi R, Cariboni A, Condorelli F, Canonico PL, Genazzani AA
Calcineurin Primes Immature GnRH-Secreting Neuroendocrine Cells for Migration.
Mol Endocrinol. 2007 Nov 21;
During development, many neurons display calcium-dependent migration, but the role of this messenger in regulating gene expression leading to this event has not yet been elucidated. Among the decoders of calcium signals is calcineurin, a Ca(2+)/CaM serine/threonine phosphatase that has been involved in both short term and long-term cellular changes. By using immortalised GnRH-secreting neurons, we now show that, in vitro, Ca(2+)-dependent gene expression, proceeding via calcineurin and the transcription factor NFAT, is a key player controlling the chemomigratory potential of developing GnRH-secreting neurons. Furthermore, our data highlight the "switch" nature of this phosphatase, whose activation or inactivation guides cells to proceed from one genetic program to the next. [Abstract/Link to Full Text]

Kane N, Jones M, Brosens JJ, Saunders PT, Kelly RW, Critchley HO
TGF{beta}1 attenuates expression of both the progesterone receptor and dickkopf in differentiated human endometrial stromal cells.
Mol Endocrinol. 2007 Nov 21;
TGFbeta1 is thought to be intimately involved in cyclic tissue remodelling and inflammatory events associated with menstruation. Menstruation is initiated by progesterone withdrawal; however the underlying mechanisms are not well understood. In the present study, we have tested the hypothesis that locally produced TGFbeta1 may influence expression of progesterone receptor (PR), or the Wnt antagonist, Dickkopf-1 (DKK) with consequential impact on regulation of menstruation. Endometrial stromal cells (ESC) were isolated from endometrial biopsy samples collected from patients undergoing gynaecological procedures for benign indications. Treatment of differentiated ESC with TGFbeta1 (10 ng/ml) significantly inhibited the expression of mRNAs encoding PR and DKK. TGFbeta1 also attenuated the protein expression of PR and secretion of DKK proteins in culture supernatants. Neutralization of endogenous TGFbeta1 signaling abolished the TGFbeta1-induced effects, significantly increased expression of PR, and increased DKK protein release levels to that of differentiated ESCs, confirming the specificity of the TGFbeta1 effect. Additionally, in vitro decidualization of ESCs, significantly augmented DKK protein release. Moreover, although TGFbeta1 was capable of signaling via the SMAD pathway, the inhibitory effect on DKK was SMAD independent. Conversely, the inhibitory effects of TGFbeta1 on PR was dependent on SMAD signal transduction. In conclusion, these results suggest that local TGFbeta1 signaling can potentiate progesterone withdrawal by suppressing expression of PR and may coordinate tissue remodeling associated with menstruation by inducing Wnt-signaling via inhibition of DKK, which we found to be upregulated as a consequence of decidualization of ESCs. [Abstract/Link to Full Text]

Higgins KJ, Liu S, Abdelrahim M, Vanderlaag K, Liu X, Porter W, Metz R, Safe S
Vascular Endothelial Growth Factor Receptor-2 Expression is Downregulated by 17{beta}-Estradiol in MCF-7 Breast Cancer Cells By Estrogen Receptor {alpha}/Sp Proteins.
Mol Endocrinol. 2007 Nov 15;
17beta-Estradiol (E2) induces and represses gene expression in breast cancer cells; however, the mechanisms of gene repression are not well understood. In this study, we show that E2 decreases VEGFR2 mRNA levels in MCF-7 cells and this gene was used as a model for investigating pathways associated with E2-dependent gene repression. Deletion analysis of the VEGFR2 promoter indicates that the proximal GC-rich motifs at -58 and -44 are critical for the E2-dependent decreased response in MCF-7 cells. Mutation or deletion of these GC-rich elements results in loss of hormone-responsiveness and shows that the -60 to -37 region of the VEGFR2 promoter is critical for both basal and hormone-dependent decreased VEGFR2 expression in MCF-7 cells. Western-blot, immunofluorescent staining, RNA interference, and electrophoretic mobility shift assays support a role for Sp proteins in hormone-dependent downregulation of VEGFR2 in MCF-7 cells, primarily through ERalpha/Sp1 and ERalpha/Sp3 interactions with the VEGFR2 promoter. Using chromatin immunoprecipitation and transient transfection/RNA interference assays we show that the ERalpha/Sp protein-promoter interactions are accompanied by recruitment of the corepressors SMRT and NCoR to the promoter and that SMRT and NCoR knockdown reverse E2-mediated downregulation of VEGFR2 expression in MCF-7 cells. This study illustrates that both SMRT and NCoR are involved in E2-dependent repression of VEGFR2 in MCF-7 cells. [Abstract/Link to Full Text]

Lu M, Tang Q, Olefsky JM, Mellon PL, Webster NJ
ADIPONECTIN ACTIVATES AMPK AND DECREASES LUTEINIZING HORMONE SECRETION IN L{beta}T2 GONADOTROPES.
Mol Endocrinol. 2007 Nov 15;
Metabolic dysregulation is associated with reproductive disorders but the underlying mechanisms are not clearly understood. Adiponectin is an adipocyte-derived secretory factor that improves insulin sensitivity. Results from animal models indicate that overexpression of adiponectin impairs female fertility. We hypothesized that adiponectin regulates reproduction by altering the hypothalamic-pituitary axis. Mouse LbetaT2 immortalized gonadotrope cells express both adiponectin receptors 1 and 2. Adiponectin increases phosphorylation of AMPK, a downstream target of adiponectin receptors, and reduces basal and GnRH-stimulated LH secretion, acutely. The repression of LH secretion can be mimicked by AICAR, an AMP analog, suggesting the involvement of AMPK. A dominant-negative AMPK mutant or compound C, a selective AMPK inhibitor, potentiates basal LH secretion and abolishes the inhibitory effect of adiponectin. Chronic activation of AMPK by AICAR decreases cellular LH levels and expression of dominant negative AMPK increases cellular LH levels, suggesting a second effect of AMPK to regulate LH synthesis. Lastly, intravenous injection of an adenovirus expressing adiponectin into male mice reduces serum LH levels without changing FSH levels. In conclusion, our results suggest that adiponectin decreases LH secretion in pituitary gonadotropes in an AMPK-dependent manner. [Abstract/Link to Full Text]

Rüegg J, Swedenborg E, Wahlström D, Escande A, Balaguer P, Pettersson K, Pongratz I
The transcription factor ARNT functions as an estrogen receptor beta selective co-activator, and its recruitment to alternative pathways mediates anti-estrogenic effects of TCDD.
Mol Endocrinol. 2007 Nov 8;
The biological effects of dioxins are mediated by the Aryl hydrocarbon receptor (AhR) and its dimerisation partner, the AhR nuclear translocator (ARNT), and include interference with hormonal signalling pathways like the response to estrogens. The effects of estrogens are mediated by two estrogen receptor (ER) isoforms, ERalpha and ERbeta, which belong to the family of nuclear receptors. We have previously shown that ARNT can act as co-activator of the ERs,. In this study, we show that recruitment of ARNT to AhR- or HIF-1alpha-signalling pathways, as well as siRNA-mediated down-regulation of ARNT levels, leads to a reduction in ER transcriptional activity. Using ChIP assays, we demonstrate that this decrease coincides with reduced recruitment of ARNT to estradiol-regulated promoters. We show further that co-activation by ARNT as well as inhibition by dioxin acts stronger on ERbeta than on ERalpha activity. Additionally, we demonstrate that the effects of ARNT are dependent on the A/B domain of the estrogen receptors with A/B domain of ERbeta being considerable stronger in mediating the coactivating effects of ARNT. Taken together, our studies show that recruitment of ARNT to the AhR following dioxin treatment can account for the anti-estrogenic effect of dioxins. Moreover, we show for the first time that the inhibitory effects of dioxin are more pronounced on ERbeta than on ERalpha. [Abstract/Link to Full Text]

Goodyer CG, Rhani Z, Zheng H
EXPRESSION OF THE HEPATIC SPECIFIC V1 mRNA OF THE HUMAN GROWTH HORMONE RECEPTOR GENE IS REGULATED BY HNF-4{alpha}2 and HNF-4{alpha}8.
Mol Endocrinol. 2007 Nov 8;
Human growth hormone (hGH) plays an essential role in growth and metabolism and its effectiveness is modulated by the availability of its specific receptor (hGHR) on target cells. The hGHR gene has a complex 5'regulatory region containing multiple first exons. Seven are clustered within two small regions: V2,V3,V9 (Module A) and V1,V4,V7,V8 (Module B). Module A-derived mRNAs are ubiquitously expressed while those from Module B are only found in postnatal liver, suggesting developmental- and liver-specific regulation of Module B hGHR gene expression. To characterize the elements regulating Module B activity, we studied a 1.8kb promoter of the highest expressing exon in liver, V1. This promoter was repressed in transfection assays; however, either 5' or 3' deletions relieved this, suggesting the presence of multiple negative regulatory elements. Six putative hepatic nuclear factor 4 (HNF-4) response elements were identified. We determined that HNF-4alpha is developmentally regulated in the human liver: HNF-4alpha2 and HNF-4alpha8 are expressed in fetal hepatocytes but only HNF-4alpha2 in postnatal liver. Transient transfection assays demonstrated that HNF-4alpha2 and HNF-4alpha8 have a similar dual effect on V1 transcription: activation via site #1 in the proximal promoter and repression through site #6 approximately 1.7 kb upstream. EMSA/EMSSA and ChIP analyses confirmed these two sites are bound by HNF-4alpha. Based on these data, we speculate there are multiple regions working together to repress the expression of V1 hGHR transcripts in tissues other than the normal postnatal liver, and that HNF-4alpha is a good candidate for regulating V1 hGHR expression in the human hepatocyte. [Abstract/Link to Full Text]

Yin Z, Williams-Simons L, Parlow AF, Asa S, Kirschner LS
Pituitary-specific knockout of the Carney Complex Gene Prkar1a leads to pituitary tumorigenesis.
Mol Endocrinol. 2007 Nov 1;
Carney Complex (CNC) is an inherited neoplasia syndrome characterized by spotty skin pigmentation, myxomas, endocrine tumors, and schwannomas. Among the endocrine tumors that comprise the syndrome, growth hormone-producing pituitary tumors are seen in approximately 10% of patients, although biochemical abnormalities of the growth hormone axis are much more common. In order to explore the role of loss of the CNC gene PRKAR1A on pituitary tumorigenesis, we produced a tissue specific knockout of this gene in the mouse. For these studies, we generated a mouse line expressing the cre recombinase in pituitary cells using the rat GHRH receptor promoter. These mice were then crossed with Prkar1a conditional null animals to produce tissue-specific knockouts. Although prolactinomas were observed in KO and control mice, the KO mice exhibited a significantly increased frequency of pituitary tumors compared to wild type or conventional Prkar1a(+/-) mice. Characterization of the tumors demonstrated they were composed of cells of the Pit1 lineage that stained for GH, Prolactin, and TSH. At the biochemical level, levels of GH in the serum of KO animals were markedly elevated compared to controls, regardless of the presence of a frank tumor. These data indicate that complete loss of Prkar1a is sufficient to allow the formation of pituitary tumors and abnormalities of the GH axis, in close analogy to human patients with CNC. [Abstract/Link to Full Text]

Fitzsimons CP, Ahmed S, Wittevrongel C, Schouten TG, Dijkmans TF, Scheenen WJ, Schaaf MJ, de Kloet ER, Vreugdenhil E
The microtubule associated protein Doublecortin-like regulates the transport of the glucocorticoid receptor in neuronal progenitor cells.
Mol Endocrinol. 2007 Nov 1;
In neuronal cells, activated glucocorticoid receptor (GR) translocates to the nucleus guided by the cytoskeleton. However, the detailed mechanisms underlying GR translocation remain unclear. Using gain and loss of function studies, we report here for the first time that the microtubule-associated protein doublecortin-like (DCL) controls GR translocation to the nucleus. DCL over-expression in COS-1 cells, neuroblastoma cells and rat hippocampus organotypic slice cultures impaired GR translocation and decreased GR-dependent transcriptional activity, measured by a specific reporter gene assay, in COS-1 cells. Moreover, DCL and GR directly interact on microtubule bundles formed by DCL over-expression. A C-terminal truncated DCL with conserved microtubule bundling activity did not influence GR translocation. In N1E-115 mouse neuroblastoma cells and neuronal progenitor cells in rat hippocampus organotypic slice cultures, laser-scanning confocal microscopy showed co-labeling of endogenously expressed DCL and GR. In these systems, RNA-interference-mediated DCL knockdown hampered GR translocation. Thus, we conclude that DCL expression is tightly regulated to adequately control GR transport. As DCL is primarily expressed in neuronal progenitor cells, our results introduce this microtubule-associated protein as a new modulator of GR signaling in this cell type and suggest the existence of cell-specific mechanisms regulating GR translocation to the nucleus. [Abstract/Link to Full Text]

Das P, Ezashi T, Gupta R, Roberts RM
Combinatorial roles of protein kinase A, Ets2 and CBP/p300 in the transcriptional control of interferon-tau expression in a trophoblast cell line.
Mol Endocrinol. 2007 Nov 1;
In ruminants, conceptus IFNT production is necessary for maintenance of pregnancy. We examined the role of PKA in regulating IFNT expression through the activation of Ets2 in JAr choriocarcinoma cells. Although over-expression of the catalytic subunit of PKA or the addition of 8-bromo-cyclic AMP had little ability to up-regulate boIFNT1 reporter constructs on their own, co-expression with Ets2 led to a large increase in gene expression. Progressive truncation of reporter constructs indicated that the site of PKA/Ets2 responsiveness lay in a region of the promoter between -126 and -67, which lacks a cAMP response element (CRE) but contains the functional Ets2-binding site and an AP1 site. Specific mutation of the former reduced the PKA/Ets2 effects by more than 98%, whereas mutation of an AP1 binding site adjacent to the Ets2 site or pharmacological inhibition of MEK2 led to a doubling of the combined Ets2/PKA effects, suggesting there is antagonism between the Ras/MAPK pathway and the PKA signal transduction pathway. Although Ets2 is not a substrate for PKA, lowering the effective concentrations of the co-activators, CBP/p300, known PKA targets, reduced the ability of PKA to synergize with Ets2, suggesting that PKA effects on IFNT regulation might be mediated through CBP/p300 co-activation, particularly as CBP and Ets2 occupy the proximal promoter region of IFNT in bovine trophoblast CT-1 cells. The up-regulation of IFNT in the elongating bovine conceptus is likely due to the combinatorial effects of PKA, Ets2 and CBP/p300 and triggered via growth factors released from maternal endometrium. [Abstract/Link to Full Text]

Ko S, Shi L, Kim S, Song CS, Chatterjee B
Interplay of NF-{kappa}B and B-myb in the negative regulation of androgen receptor expression by TNF{alpha}
Mol Endocrinol. 2007 Nov 1;
Increased androgen receptor (AR) levels are associated with prostate cancer progression to androgen independence and therapy resistance. Evidence has suggested that chronic inflammation is closely linked to various cancers including prostate cancer. Herein we show that the pro-inflammatory cytokine TNFalpha negatively regulates AR mRNA and protein expression, and reduces androgen sensitivity in androgen-dependent LNCaP human prostate cancer cells. Decreased AR expression results from transcription repression involving essential in cis interaction of NF-kappaB with the B-myb transcription factor at a composite genomic element in the 5' UTR of AR. The negative regulation was abrogated when NF-kappaB activity was inhibited by a superrepressor of the inhibitory kappaB (IkappaB) protein. Contrastingly, androgen-independent C4-2 (LNCaP-derived) cells fail to show AR down regulation by TNFalpha, despite expression of B-myb and TNFalpha-induced NF-kappaB activity similarly to that in LNCaP cells. The negatively regulated AR gene chromatin region showed TNFalpha-dependent enrichment of B-myb and the NF-kappaB proteins p65 and p50. In parallel, the histone deacetylase HDAC1, corepressor SMRT and the corepressor-associated scaffold protein mSin3A were recruited to the inhibitory site. In C4-2 cells, neither NF-kappaB and B-myb, nor any of the corepressor components, were detected at the negative site in response to TNFalpha. Apoptosis was induced in TNFalpha-treated LNCaP cells, likely in part due to the down regulation of AR. The androgen-independent, AR-expressing C4-2 and C4-2B (derived from C4-2) cells were resistant to TNFalpha-induced apoptosis. The results linking androgen dependence to NF-kappaB and AR pathways may be insightful in identifying novel treatment targets for prostate cancer. [Abstract/Link to Full Text]

Shearer BG, Steger DJ, Way JM, Stanley TB, Lobe DC, Grillot DA, Iannone MA, Lazar MA, Willson TM, Billin AN
Identification and characterization of a selective PPAR{beta}/{delta} (NR1C2) antagonist.
Mol Endocrinol. 2007 Nov 1;
The identification of small molecule ligands for the peroxisome proliferator activated receptors (PPARs) has been instrumental in elucidating their biological roles. In particular, agonists have been the focus of much of the research in the field with relatively few antagonists being described and all of those being selective for PPARalpha or PPARgamma. The comparison of these agonist and antagonist ligands in cellular and animal systems has often lead to surprising results and new insights into the biology of the PPARs. The PPARbeta/delta receptor is emerging as an important regulator of energy metabolism, inflammation, and cell growth and differentiation, however only agonist ligands have been described for this receptor thus far. Here we describe the first report of a PPARbeta/delta small molecule antagonist ligand. This antagonist ligand will be a useful tool for elucidating the biological roles of PPARbeta/delta. [Abstract/Link to Full Text]

Halperin J, Devi SY, Elizur S, Stocco C, Shehu A, Rebourcet D, Unterman TG, Leslie ND, Le J, Binart N, Gibori G
Prolactin Signaling Through the Short Form of Its Receptor Represses FOXO3 and its Target Gene Galt Causing a Severe Ovarian Defect.
Mol Endocrinol. 2007 Nov 1;
Prolactin is a hormone with over 300 biological activities. Although the signaling pathway downstream of the long form of its receptor (RL) has been well characterized, little is known about PRL actions upon activation of the short form (RS). Here, we show that mice expressing only RS exhibit an ovarian phenotype of accelerated follicular recruitment followed by massive follicular death leading to premature ovarian failure (POF). Consequently, RS-expressing ovaries of young adults are depleted of functional follicles and formed mostly by interstitium. We also show that activation of RS represses the expression of the transcription factor FOXO3 and that of the enzyme galactose-1-phosphate urydiltransferase (Galt), two proteins known to be essential for normal follicular development. Our finding that FOXO3 regulates the expression of Galt and enhances its transcriptional activity indicates that it is the repression of FOXO3 by PRL acting through RS that prevent Galt expression in the ovary and causes follicular death. Co-expression of RL with RS prevents PRL inhibition of Galt, and the ovarian defect is no longer seen in RS transgenic mice that co-express RL, suggesting that RL prevents RS-induced ovarian impairment. In summary, we show that prolactin signals through RS and causes, in absence of RL, a severe ovarian pathology by repressing the expression of FOXO3 and that of its target gene Galt. We also provide evidence of a link between the POF seen in mice expressing RS, in mice with FOXO3 gene deletion as well as in human with Galt mutation. [Abstract/Link to Full Text]

Yamakawa T, Whitson RH, Li SL, Itakura K
Modulator recognition factor-2 is required for adipogenesis in mouse embryo fibroblasts and 3T3-L1 cells.
Mol Endocrinol. 2007 Oct 25;
Previous study showed that mice lacking modulator recognition factor-2 (Mrf-2) were lean, with significant decreases in white adipose tissue. One postulated mechanism for the lean phenotype in Mrf-2 knockout mice is a defect in adipogenesis. In order to investigate this further, we examined the effects of Mrf-2 deficiency on adipogenesis in vitro. In mouse fibroblasts (MEFs) derived from Mrf-2(-/-) embryos, and in 3T3-L1 cells following knockdown of Mrf-2 by small interference RNA (siRNA) there was a potent inhibition of hormone-induced lipid accumulation, and significant decreases in the expression of the adipogenic transcription factors C/EBPalpha and PPARgamma and the mature adipocyte genes they control. Transduction of Mrf-2(-/-) MEFs with a retroviral vector expressing the longer Mrf-2 splice variant (Mrf-2B) stimulated both gene expression and lipid accumulation. Because 3T3-L1 cells are committed to the adipocyte lineage, we used this simpler model system to examine the effects of Mrf-2 deficiency on adipocyte maturation. Analyses of both mRNA and protein revealed that knockdown of Mrf-2 in 3T3-L1 cells prolonged the expression of CHOP-10, a dominant negative form of C/EBP. Consistent with these findings, suppression of Mrf-2 also inhibited the DNA-binding activity of C/EBPbeta. These data suggest that Mrf-2 facilitates the induction of the two key adipogenic transcription factors C/EBPalpha and PPARgamma indirectly by permitting hormone-mediated repression of the adipogenic repressor CHOP-10. [Abstract/Link to Full Text]

Denger S, Bähr-Ivacevic T, Brand H, Reid G, Blake J, Seifert M, Lin CY, May K, Benes V, Liu ET, Gannon F
Transcriptome profiling of estrogen-regulated genes in human primary osteoblasts reveals an osteoblast specific regulation of the IGFBP4 gene.
Mol Endocrinol. 2007 Oct 25;
Estradiol (E2) is believed to modulate physiological functions relevant to osteoblast biology through the actions of estrogen receptors (ER) that in turn regulate the expression of target genes. The molecular effects of estrogen action in bone remain to be fully elucidated. This study reports a genome-wide molecular and computational analysis of the interaction between estrogen receptor (ER) and regulatory elements on the DNA of target genes in human primary osteoblasts. Of approximately 54000 gene probes surveyed in this study, a total of 375 genes were upregulated and 418 genes were downregulated on exposure to estradiol, with only 46 of these being direct target genes after 24 h, as determined by concomitant cycloheximide treatment. Computational analysis discovered several pathways where E2 co-regulates multiple functionally linked components. Examination of the genomic sequence of insulin growth factor binding protein 4 (IGFBP4) located ER response elements within the first intron. Using chromatin immunoprecipitation (ChIP) we show a site-and cell-specific recruitment of transcription factors to this newly identified regulatory region. Transient transfection studies revealed that this intronic region acts as a functional promoter in human osteoblasts. Taken together, this analysis provides a comprehensive gene transcription profile and identifies several genes of potential physiological importance in controlling estrogen mediated signaling in primary osteoblasts. [Abstract/Link to Full Text]

Levy N, Tatomer D, Herber CB, Zhao X, Tang H, Sargeant T, Ball LJ, Summers J, Speed TP, Leitman DC
Differential regulation of Native Estrogen Receptor Regulatory Elements by Estradiol, Tamoxifen, and Raloxifene.
Mol Endocrinol. 2007 Oct 25;
Estrogen receptors (ER) regulate gene transcription by interacting with regulatory elements. Most information regarding how ER activates genes has come from studies using a small set of target genes or simple consensus sequences such as ERE, AP-1 and Sp1 elements. However, these elements cannot explain the differences in gene regulation patterns and clinical effects observed with E2 and SERMs. To obtain a greater understanding of how E2 and SERMs differentially regulate genes it is necessary to investigate their action on a more comprehensive set of native regulatory elements derived from ER target genes. Here we used chromatin immunoprecipitation-cloning and sequencing (ChIP-CS) to isolate 173 regulatory elements associated with ERalpha. Most elements were found in the introns (38%) and regions greater than 10 kB upstream of the transcription intiation site (38%). 24% of the elements were found in the proximal promoter region (<10 kB). Only 11% of the elements contained a classical ERE. 23% of the elements did not have any known response elements, including one derived from the naked cuticle homolog gene, which was associated with the recruitment of p160 coactivators. Transfection studies found that 80% of the 173 elements were regulated by E2, raloxifene or tamoxifen with ERalpha or ERbeta. Tamoxifen was more effective than raloxifene at activating the elements with ERalpha, whereas raloxifene was superior with ERbeta. Our findings demonstrate that E2, tamoxifen and raloxifene differentially regulate native ER regulatory elements isolated by ChIP with ERalpha and ERbeta. [Abstract/Link to Full Text]

Picard N, Charbonneau C, Sanchez M, Licznar A, Busson M, Lazennec G, Tremblay A
Phosphorylation of Activation Function-1 Regulates Proteasome-dependent Nuclear Mobility and E6-AP Ubiquitin Ligase Recruitment to the Estrogen Receptor {beta}
Mol Endocrinol. 2007 Oct 25;
The ubiquitin-proteasome pathway has been recognized as an important regulator in the hormonal response by estrogen receptor ERalpha, but its impact on ERbeta function is poorly characterized. In the current study, we investigated the role of the ubiquitin-proteasome pathway in regulating ERbeta activity and identified regulatory sites within the activation function AF-1 domain that modulate ERbeta ubiquitination and nuclear dynamics in a hormone-independent manner. Whereas both ERalpha and ERbeta were dependent on proteasome function for their maximal response to estrogen, they were regulated differently by proteasome inhibition in the absence of hormone, an effect shown to be dependent on their respective AF-1 domain. Given the role of AF-1 phosphorylation to regulate ER activity, we found that sequential substitutions of specific serine residues contained in MAPK consensus sites conferred transcriptional activation of ERbeta in a proteasome-dependent manner through reduced ubiquitination and enhanced accumulation of mutant receptors. Specifically, serines 94 and 106 within ERbeta AF-1 domain were found to modulate sub-nuclear mobility of the receptor to transit between inactive clusters and a more mobile state in a proteasome-dependent manner. In addition, cellular levels of ERbeta were regulated through these sites by facilitating the recruitment of the ubiquitin ligase E6-associated protein in a phosphorylation-dependent manner. These findings suggest a role for ERbeta AF-1 in contributing to the activation-degradation cycling of the receptor through a functional clustering of phosphorylated serine residues that cooperate in generating signals to the ubiquitin-proteasome pathway. [Abstract/Link to Full Text]

Chen L, Maures TJ, Jin H, Huo JS, Rabbani SA, Schwartz J, Carter-Su C
SH2B1{beta} (SH2-B{beta}) ENHANCES EXPRESSION OF A SUBSET OF NERVE GROWTH FACTOR-REGULATED GENES IMPORTANT FOR NEURONAL DIFFERENTIATION INCLUDING GENES ENCODING UPAR AND MMP3/10.
Mol Endocrinol. 2007 Oct 18;
Previous work showed that the adapter protein SH2B1 (SH2-B) binds to the activated form of the nerve growth factor (NGF) receptor TrkA and is critical for both NGF-dependent neurite outgrowth and maintenance. To identify SH2B1beta regulated genes critical for neurite outgrowth, we performed microarray analysis of control PC12 cells and PC12 cells stably overexpressing SH2B1beta (PC12-SH2B1beta) or the dominant negative SH2B1beta(R555E) (PC12-SH2B1beta[R555E]). NGF-induced microarray expression of Plaur and Mmp10 genes was greatly enhanced in PC12-SH2B1beta cells while NGF-induced Plaur and Mmp3 expression was substantially depressed in PC12-SH2B1beta(R555E) cells. Plaur, Mmp3 and Mmp10 are among the 12 genes most highly upregulated after 6 h of NGF. Their protein products (uPAR, MMP3, MMP10) lie in the same pathway of extracellular matrix degradation; uPAR has been shown previously to be critical for NGF-induced neurite outgrowth. QT-PCR analysis revealed SH2B1beta-enhancement of NGF-induction of all three genes and the suppression of NGF-induction of all three when endogenous SH2B1 was reduced using shRNA against SH2B1 and in PC12-SH2B1beta(R555E) cells. NGF-induced levels of uPAR and MMP3/10 and neurite outgrowth through Matrigel (MMP3-dependent) were also increased in PC12-SH2B1beta cells. These results suggest that SH2B1beta stimulates NGF-induced neuronal differentiation at least in part by enhancing expression of a specific subset of NGF-sensitive genes, including Plaur, Mmp3 and/or Mmp10, required for neurite outgrowth. [Abstract/Link to Full Text]

Lin SY, Craythorn RG, O'connor AE, Matzuk MM, Girling JE, Morrison JR, de Kretser DM
Female infertility and disrupted angiogenesis are actions of specific follistatin isoforms.
Mol Endocrinol. 2007 Oct 11;
The circulating (FST315) and tissue bound (FST288) forms of follistatin modulate the actions of activins. Follistatin knockout (KO/null) mice, lacking both isoforms, die perinatally with defects in lung, skin and the musculoskeletal system. Using constructs of the human follistatin gene engineered to enable expression of each isoform under the control of natural regulatory elements, transgenic mouse lines were created and crossed with follistatin null mice to attempt to rescue the neonatal lethality. FST288 expression alone did not rescue the neonatal lethality, but mice expressing FST315 on the KO background survived to adulthood with normal lung and skin morphology and partial reversal of the musculoskeletal defects noted in follistatin KO mice. The FST315 "rescue" mice displayed a short period of neonatal growth retardation, impaired tail growth and female infertility. The latter may be due to failure of corpus luteum formation, a decline in the ovarian follicular population and an augmented uterine inflammatory response to mating. Failure of corpus luteum formation and impaired tail growth indicate abnormal vascularization and suggest that FST288 is required for the promotion of angiogenesis. The augmented uterine inflammatory response may result from the failure of FST315 to modulate the pro-inflammatory actions of activin A in the uterus or may result from the altered steroid milieu associated with the ovarian abnormalities. While we cannot definitively conclude that the remaining defects are due to the absence of a particular isoform or due to variable expression of each, these models have demonstrated novel physiological processes that are influenced by follistatin. [Abstract/Link to Full Text]

Shrivastav S, Kino T, Cunningham T, Ichijo T, Schubert U, Heinklein P, Chrousos GP, Kopp JB
HIV-1 Vpr suppresses transcriptional activity of PPAR{gamma} and inhibits adipocyte differentiation: Implications for HIV-associated lipodystrophy.
Mol Endocrinol. 2007 Oct 11;
HIV-1-infected patients may develop lipodystrophy and insulin resistance. We investigated the effect of the HIV-1 accessory protein Vpr on the activity of the peroxisomal proliferator-activating receptor-gamma (PPARgamma), a key regulator of adipocyte differentiation and tissue insulin sensitivity. We studied expression of PPARgamma responsive reporter genes in 3T3-L1 mouse adipocytes. We investigated Vpr interaction with the PPAR/RXR-binding site of the c-Cbl associating protein (CAP) gene using the chromatin immunoprecipitation assay, as well as the interaction of Vpr and PPARgamma using co-immunoprecipitation. Finally, we studied the ability of exogenous Vpr protein to enter cultured adipocytes and retard differentiation. We found that Vpr suppressed PPARgamma-induced transactivation in both undifferentiated and differentiated 3T3-L1 cells. Transcriptional suppression by Vpr required an intact LXXLL coactivator motif. Vpr suppressed mRNA expression of PPARgamma-responsive genes in undifferentiated 3T3-L1 cells and associated with the PPAR/RXR-binding site located in the promoter region of the CAP gene. Vpr interacted with the ligand-binding domain of PPARgamma in an agonist-dependent fashion in vitro. Vpr delivered either by an expression plasmid or as protein added to media suppressed PPARgamma agonist-induced adipocyte differentiation, assessed as lipid accumulation and mRNA expression of the adipocyte differentiation marker aP2 in 3T3-L1 cells. In conclusion, circulating Vpr, or alternatively Vpr produced as a consequence of direct infection of adipocytes, could suppress in vivo differentiation of preadipocytes by acting as a corepressor of PPARgamma-mediated gene transcription. Vpr may alter sensitivity to insulin and thereby contribute to the development of lipodystrophy and insulin resistance observed in HIV-1-infected patients. [Abstract/Link to Full Text]

Bassett JH, Williams AJ, Murphy E, Boyde A, Howell PG, Swinhoe R, Archanco M, Flamant F, Samarut J, Costagliola S, Vassart G, Weiss RE, Refetoff S, Williams GR
A lack of thyroid hormones rather than excess TSH causes abnormal skeletal development in hypothyroidism.
Mol Endocrinol. 2007 Oct 11;
By proposing thyrotropin (TSH) as a key negative regulator of bone turnover, recent studies in TSH receptor (TSHR) null mice challenged the established view that skeletal responses to disruption of the hypothalamic-pituitary-thyroid (HPT) axis result from altered thyroid hormone (T3) action in bone. Importantly, this hypothesis does not explain the increased risk of osteoporosis in Graves' disease patients, in which circulating TSHR-stimulating antibodies are pathognomonic. To determine the relative importance of T3 and TSH in bone, we compared the skeletal phenotypes of two mouse models of congenital hypothyroidism in which the normal reciprocal relationship between thyroid hormones and TSH was intact or disrupted. Pax8 null (Pax8(-/-)) mice have a 1900-fold increase in TSH and a normal TSHR, whereas hyt/hyt mice have 2300-fold elevation of TSH but a non-functional TSHR. We reasoned these mice must display opposing skeletal phenotypes if TSH has a major role in bone, whereas they would be similar if thyroid hormone actions predominate. Pax8(-/-) and hyt/hyt mice both displayed delayed ossification, reduced cortical bone, a trabecular bone remodeling defect and reduced bone mineralization, thus indicating that the skeletal abnormalities of congenital hypothyroidism are independent of TSH. Treatment of primary osteoblasts and osteoclasts with TSH or a TSHR-stimulating antibody failed to induce a cAMP response. Furthermore, TSH did not affect the differentiation or function of osteoblasts or osteoclasts in vitro. These data indicate the HPT axis regulates skeletal development via the actions of T3. [Abstract/Link to Full Text]

Nettles KW, Gil G, Nowak J, Métivier R, Sharma VB, Greene GL
CBP is a dosage dependent regulator of NF{kappa}B suppression by the estrogen receptor.
Mol Endocrinol. 2007 Oct 11;
The estrogen receptor (ER) protects against debilitating effects of the inflammatory response by inhibiting the pro-inflammatory transcription factor NFkappaB. Heretofore CBP has been suggested to mediate inhibitory cross-talk by functioning either as a scaffold that links ER and NFkappaB or as a required cofactor that competitively binds to one or the other transcriptional factor. However, here we demonstrate that ER is recruited to the NFkappaB response element of the MCP-1 and IL-8 promoters and displaces CBP, but not p65 in the MCF-7 breast cancer cell line. In contrast, ER displaced p65 and associated coregulators from the IL-6 promoter, demonstrating a gene specific role for CBP in integrating inflammatory and steroid signaling. Further, RNA interference and over-expression studies demonstrated that CBP dosage regulates estrogen-mediated suppression of MCP-1 and IL-8, but not IL-6 gene expression. This work further demonstrates that CBP dosage is a critical regulator of gene-specific signal integration between the ER and NFkappaB signaling pathways. [Abstract/Link to Full Text]

Pavel E, Nadella K, Towns WH, Kirschner LS
Mutation of Prkar1a Causes Osteoblast Neoplasia Driven by Dysregulation of PKA.
Mol Endocrinol. 2007 Oct 11;
Carney Complex (CNC) is an autosomal dominant neoplasia syndrome caused by inactivating mutations in PRKAR1A, the gene encoding the type 1A regulatory subunit of protein kinase A (PKA). This genetic defect induces skin pigmentation, endocrine tumors, myxomas, and schwannomas. Some patients with the complex also develop myxoid bone tumors termed osteochondromyxomas. In order to study the link between the PRKAR1A mutations and tumor formation, we generated a mouse model of this condition. Prkar1a(+/-) mice develop bone tumors with high frequency, although these lesions have not yet been characterized, either from human patients or from mice. Bone tumors from Prkar1a(+/-) mice were heterogeneous, including elements of myxomatous, cartilaginous and bony differentiation which effaced the normal bone architecture. Immunohistochemical analysis identified an osteoblastic origin for the abnormal cells associated with islands of bone. To better understand these cells at the biochemical level, we isolated primary cultures of tumoral bone and compared them to cultures of bone from wild-type animals. The tumor cells exhibited the expected decrease in Prkar1a protein and exhibited increased PKA activity. At the phenotypic level, we observed that tumor cells behaved as incompletely differentiated osteoblasts and were able to form tumors in immunocompromised mice. Examination of gene expression revealed down-regulation of markers of bone differentiation and increased expression of locally acting growth factors, including members of the Wnt signaling pathway. Tumor cells exhibited enhanced growth in response to PKA-stimulating agents, suggesting that tumorigenesis in osteoblast precursor cells is driven by effects directly mediated by the dysregulation of PKA. [Abstract/Link to Full Text]

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Recent Articles in BMC Endocrine Disorders

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Harish K, Dharmalingam M, Himanshu M
Study protocol: Insulin and its role in cancer.
BMC Endocr Disord. 2007 Oct 22;7(1):10.
ABSTRACT: BACKGROUND: Studies have shown that metabolic syndrome and its consequent biochemical derangements in the various phases of diabetes may contribute to carcinogenesis. A part of this carcinogenic effect could be attributed to hyperinsulinism. High levels of insulin decrease the production of IGF-1 binding proteins and hence increase levels of free IGF-1. It is well established that bioactivity of free insulin growth factor 1 (IGF-1) increases tumor turnover rate. The objective is to investigate the role of insulin resistance/sensitivity in carcinogenesis by studying the relation between insulin resistance/sensitivity and IGF-1 levels in cancer patients. We postulate that hyperinsulinaemia which prevails during initial phases of insulin resistance (condition prior to overt diabetes) increases bioactivity of free IGF-1, which may contribute to process of carcinogenesis. Methods / Design: Based on our pilot study results and power analysis of the same, we have designed a two group case-control study. 800 proven untreated cancer patients (solid epithelial cell tumors) under age of 50 shall be recruited with 200 healthy subjects serving as controls. Insulin resistance/sensitivity and free IGF-1 levels shall be determined in all subjects. Association between the two parameters shall be tested using suitable statistical methods. DISCUSSION: Well controlled studies in humans are essential to study the link between insulin resistance, hyperinsulinaemia, IGF-1 and carcinogenesis. This study could provide insights to the role of insulin, insulin resistance, IGF-1 in carcinogenesis although a precise role and the extent of influence cannot be determined. In future, cancer prevention and treatment strategies could revolve around insulin and insulin resistance. [Abstract/Link to Full Text]

Holvik K, Meyer HE, Sogaard AJ, Haug E, Falch JA
Pakistanis living in Oslo have lower serum 1,25-dihydroxyvitamin D levels but higher serum ionized calcium levels compared with ethnic Norwegians. The Oslo Health Study.
BMC Endocr Disord. 2007 Oct 18;7(1):9.
ABSTRACT: BACKGROUND: Persons of Pakistani origin living in Oslo have a much higher prevalence of vitamin D deficiency and secondary hyperparathyroidism but similar bone mineral density compared with ethnic Norwegians. Our objective was to investigate whether Pakistani immigrants living in Oslo have an altered vitamin D metabolism by means of compensatory higher serum levels of 1,25-dihydroxyvitamin D (s-1,25(OH)2D) compared with ethnic Norwegians; and whether serum levels of ionized calcium (s-Ca2+) differ between Pakistanis and Norwegians. METHODS: In a cross-sectional, population-based study venous serum samples were drawn from 94 Pakistani men and 67 Pakistani women aged 30-60 years, and 290 Norwegian men and 270 Norwegian women aged 45-60 years; in total 721 subjects. RESULTS: Pakistanis had lower s-1,25(OH)2D compared with Norwegians (p<0.001). Age- and gender adjusted mean (95% CI) levels were 93 (86, 99) pmol/l in Pakistanis and 123 (120, 126) pmol/l in Norwegians, p<0.001. The difference persisted after controlling for body mass index. There was a positive relation between serum 25-hydroxyvitamin D (s-25(OH)D) and s-1,25(OH)2D in both groups. S-Ca2+ was higher in Pakistanis; age-adjusted mean (95% CI) levels were 1.28 (1.27, 1.28) mmol/l in Pakistanis and 1.26 (1.26, 1.26) mmol/l in Norwegians, p<0.001. In both groups, s-Ca2+ was inversely correlated to serum intact parathyroid hormone levels (s-iPTH). For any s-iPTH, s-Ca2+ was higher in Pakistanis, also when controlling for age. CONCLUSIONS: Community-dwelling Pakistanis in Oslo with low vitamin D status and secondary hyperparathyroidism have lower s-1,25(OH)2D compared with ethnic Norwegians. However, the Pakistanis have higher s-Ca2+. The cause of the higher s-Ca2+ in Pakistanis in spite of their higher iPTH remains unclear. [Abstract/Link to Full Text]

Costa-Guda J, Tokura T, Roth SI, Arnold A
Mitochondrial DNA mutations in oxyphilic and chief cell parathyroid adenomas.
BMC Endocr Disord. 2007;78.
ABSTRACT: BACKGROUND: The potential pathogenetic significance of mitochondrial DNA (mtDNA) mutations in tumorigenesis is controversial. We hypothesized that benign tumorigenesis of a slowly replicating tissue like the human parathyroid might constitute an especially fertile ground on which a selective advantage conferred by mtDNA mutation could be manifested and might contribute to the oxyphilic phenotype observed in a subset of parathyroid tumors. METHODS: We sought acquired mitochondrial DNA mutations by sequencing the entire 16.6 kb mitochondrial genome of each of thirty sporadic parathyroid adenomas (18 chief cell and 12 oxyphil cell), eight independent, polyclonal, parathyroid primary chief cell hyperplasias plus corresponding normal control samples, five normal parathyroid glands, and one normal thyroid gland. RESULTS: Twenty-seven somatic mutations were identified in 15 of 30 (9 of 12 oxyphil adenomas, 6 of 18 chief cell) parathyroid adenomas studied. No somatic mutations were observed in the hyperplastic parathyroid glands. CONCLUSION: Features of the somatic mutations suggest that they may confer a selective advantage and contribute to the molecular pathogenesis of parathyroid adenomas. Importantly, the statistically significant differences in mutation prevalence in oxyphil vs. chief cell adenomas also suggest that mtDNA mutations may contribute to the oxyphil phenotype. [Abstract/Link to Full Text]

Iwalokun BA, Iwalokun SO
Association between erythrocyte Na+K+-ATPase activity and some blood lipids in type 1 diabetic patients from Lagos, Nigeria.
BMC Endocr Disord. 2007;77.
ABSTRACT: BACKGROUND: Altered levels of erythrocyte Na+K+-ATPase, atherogenic and anti-atherogenic lipid metabolites have been implicated in diabetic complications but their pattern of interactions remains poorly understood.This study evaluated this relationship in Nigerian patients with Type 1 diabetes mellitus. METHODS: A total of 34 consented Type 1 diabetic patients and age -matched 27 non-diabetic controls were enrolled. Fasting plasma levels of total cholesterol, triglycerides and HDL-cholesterol were determined spectrophotometrically and LDL-cholesterol estimated using Friedewald formula. Total protein content and Na+K+-ATPase activity were also determined spectrophotometrically from ghost erythrocyte membrane prepared by osmotic lysis. RESULTS: Results indicate significant (P < 0.05) reduction in Na+K+-ATPase activity in the Type 1 diabetic patients (0.38 +/- 0.08 vs. 0.59 +/- 0.07 uM Pi/mgprotein/h) compared to the control but with greater reduction in the diabetic subgroup with poor glycemic control (n = 20) and in whom cases of hypercholesterolemia (8.8%), hypertriglyceridemia (2.9%) and elevated LDL-cholesterol (5.9% each) were found. Correlation analyses further revealed significant (P < 0.05) inverse correlations [r = -(0.708-0.797] between all the atherogenic lipid metabolites measured and Na+K+-ATPase in this subgroup contrary to group with good glycemic control or non-diabetic subjects in which significant (P < 0.05) Na+K+-ATPase and HDL-C association were found (r = 0.427 - 0.489). The Na+K+-ATPase from the diabetic patients also exhibited increased sensitivity to digoxin and alterations in kinetic constants Vmax and Km determined by glycemic status of the patients. CONCLUSION: It can be concluded that poor glycemic control evokes greater reduction in erythrocyte Na+K+-ATPase activity and promote enzyme-blood atherogenic lipid relationships in Type 1 diabetic Nigerian patients. [Abstract/Link to Full Text]

George JT, Valdovinos AP, Thow JC, Russell I, Dromgoole P, Lomax S, Torgerson DJ, Wells T
Brief Intervention in Type 1 diabetes - Education for Self-efficacy (BITES): Protocol for a randomised control trial to assess biophysical and psychological effectiveness.
BMC Endocr Disord. 2007;76.
ABSTRACT: BACKGROUND: Self management is the cornerstone of effective preventive care in diabetes. Educational interventions that provide self-management skills for people with diabetes have been shown to reduce blood glucose concentrations. This in turn has the potential to reduce rates of complications. However, evidence to support type, quantity, setting and mode of delivery of self-management education is sparse.Objectives: To study the biophysical and psychological effectiveness of a brief psycho-educational intervention for type 1 diabetes in adults. METHODS/DESIGN: Design: Randomised controlled clinical trial.Setting: Multidisciplinary specialist diabetes centre.Hypothesis: Our hypothesis was that the brief (2.5-day) intervention would be biophysically and psychologically effective for people with type 1 diabetes.Intervention: A brief psycho-educational intervention for type 1 diabetes developed by a multi-professional team comprising of a consultant diabetologist, a diabetes specialist nurse, a specialist diabetes dietician and a clinical health psychologist and delivered in 20 hours over 2.5 days.Primary outcomes: HbA1c and severe hypoglycaemia.Secondary outcomes: Blood pressure, weight, height, lipid profile and composite psychometric scales.Participants: We shall consent and recruit 120 subjects with postal invitations sent to eligible participants. Volunteers are to be seen at randomisation clinics where independent researcher verify eligibility and obtain consent. We shall randomise 60 to BITES and 60 to standard care.Eligibility Criteria: Type 1 diabetes for longer than 12 months, multiple injection therapy for at least two months, minimum age of 18 and ability to read and write.Randomisation: An independent evaluator to block randomise (block-size = 6), to intervention or control groups using sealed envelopes in strict ascendant order. Control group will receive standard care.Assessment: Participants in both groups would attend unblinded assessments at baseline, 3, 6 and 12 months, in addition to their usual care. After the intervention, usual care would be provided.Ethics approval: York Research Ethics Committee (Ref: 01/08/016) approved the study protocol. DISCUSSION: We hope the trial will demonstrate feasibility of a pragmatic randomised trial of BITES and help quantify therapeutic effect. A follow up multi-centre trial powered to detect this effect could provide further evidence. TRIAL REGISTRATION: Current Controlled Trials ISRCTN75807800. [Abstract/Link to Full Text]

Moncayo H, Dapunt O, Moncayo R
Diagnostic accuracy of basal TSH determinations based on the intravenous TRH stimulation test: an evaluation of 2570 tests and comparison with the literature.
BMC Endocr Disord. 2007;75.
BACKGROUND: Basal TSH levels reflect the metabolic status of thyroid function, however the definition and interpretation of the basal levels of TSH is a matter of controversial debate. The aim of this study was to evaluate basal TSH levels in relation to the physiological response to i.v. TRH stimulation. METHODS: A series of 2570 women attending a specialized endocrine unit were evaluated. A standardized i.v. TRH stimulation test was carried out by applying 200 mug of TRH. TSH levels were measured both in the basal and the 30 minute blood sample. The normal response to TRH stimulation had been previously determined to be an absolute value lying between 2.5 and 20 mIU/l. Both TSH values were analyzed by cross tabulation. In addition the results were compared to reference values taken from the literature. RESULTS: Basal TSH values were within the normal range (0.3 to 3.5 mIU/l) in 91,5% of cases, diminished in 3,8% and elevated in 4.7%. Based on the response to TRH, 82.4% were considered euthyroid, 3.3% were latent hyperthyroid, and 14.3% were latent hypothyroid. Combining the data on basal and stimulated TSH levels, latent hypothyroidism was found in the following proportions for different TSH levels: 5.4% for TSH < 2.0 mIU/l, 30.2% for TSH between 2.0 and 3.0 mIU/l, 65,5% for TSH between 3.0 and 3.50 mIU/l, 87.5% for TSH between 3.5 and 4.0 mIU/l, and 88.2% for TSH between 4 and 5 mIU/l. The use of an upper normal range for TSH of 2.5 mIU/l, as recommended in the literature, misclassified 7.7% of euthyroid cases. CONCLUSION: Our analysis strategy allows us to delineate the predictive value of basal TSH levels in relation to latent hypothyroidism. A grey area can be identified for values between 3.0 and 3.5 mIU/l. [Abstract/Link to Full Text]

Viswanath AK, Avenell A, Philip S, Acharya SH, Maclennan G, Dalziel K, Pereira O, Copland SA, Bevan JS, Abraham P
Is annual surveillance of all treated hypothyroid patients necessary?
BMC Endocr Disord. 2007;74.
BACKGROUND: Annual surveillance (with thyroid function testing) is widely recommended for the long-term follow-up of treated hypothyroid patients. It is based largely on consensus opinion and there is limited evidence to support the frequency of monitoring. The majority of patients in our hospital based thyroid register are on 18 monthly follow-up. METHODS: We carried out a retrospective analysis to see if there is evidence to support more frequent testing. We used a logistic regression model to assess whether any baseline characteristics could be applied to predict an abnormal test. RESULTS: We identified 2,125 patients with a minimum of 10 years follow-up (89% female, 65% autoimmune hypothyroidism, and mean age at registration 51 years). There were 2 groups: 1182 (56%) had been allocated to 18 monthly follow-up and the rest had annual surveillance. The groups were well matched at baseline. Overall, during follow-up the 12 monthly group had more abnormal tests requiring dose adjustment. However, on logistic regression analysis, people aged less than 60 years, individuals taking < 150 mug thyroxine per day and people on 18 monthly follow-up had less abnormal tests. CONCLUSION: 18 monthly surveillance may be adequate in the long term follow-up of hypothyroid patients less than 60 years of age on a stable thyroxine dose of 100-150 mug/day where there are robust follow-up mechanisms in place. Implementing this strategy has potential for cost saving. [Abstract/Link to Full Text]

Scranton RE, Gaziano JM, Rutty D, Ezrokhi M, Cincotta A
A randomized, double-blind, placebo-controlled trial to assess safety and tolerability during treatment of type 2 diabetes with usual diabetes therapy and either Cycloset or placebo.
BMC Endocr Disord. 2007;73.
BACKGROUND: Cycloset is a quick-release formulation of bromocriptine mesylate, a dopamine agonist, which in animal models of insulin resistance and type 2 diabetes acts centrally to reduce resistance to insulin- mediated suppression of hepatic glucose output and tissue glucose disposal. In such animals, bromocriptine also reduces hepatic triglyceride synthesis and free fatty acid mobilization, manifesting decreases in both plasma triglycerides and free fatty acids. In clinical trials, morning administration of Cycloset either as monotherapy or adjunctive therapy to sulfonylurea or insulin reduces HbA1c levels relative to placebo by 0.55-1.2. Cycloset therapy also reduces plasma triglycerides and free fatty acid by approximately 25% and 20%, respectively, among those also receiving sulfonylurea therapies. The effects of once-daily morning Cycloset therapy on glycemic control and plasma lipids are demonstrable throughout the diurnal portion of the day (7 a.m. to 7 p.m.) across postprandial time points. METHODS/DESIGN: 3,095 individuals were randomized in a 2:1 ratio into a one year trial aimed to assess the safety and efficacy of Cycloset compared to placebo among individuals receiving a variety of treatments for type 2 diabetes. Eligibility criteria for this randomized placebo controlled trial included: age 30-80, HbA1c <or= 10%, diabetes therapeutic regimen consisting of diet or no more than two hypoglycemic agents or insulin with or without one additional oral agent (usual diabetes therapy; UDT). The primary safety endpoint will test the hypothesis that the rate of all-cause serious adverse events after one year of usual diabetes therapy (UDT) plus Cycloset is not greater than that for UDT plus placebo by more than an acceptable margin defined as a hazard ratio of 1.5 with a secondary endpoint analysis of the difference in the rate of serious cardiovascular events, (myocardial infarction, stroke, coronary revascularization or hospitalization for or angina or congestive heart failure). Efficacy analyses will evaluate effects of Cycloset versus placebo on change from baseline in HbA1c, fasting glucose, body weight, waist circumference, blood pressure and plasma lipids. DISCUSSION: This study will extend the current data on Cycloset safety, tolerability and efficacy in individuals with type 2 diabetes to include its effects in combination with thiazolodinediones, insulin secretagogues, metformin, alpha-glucosidase inhibitors and exogenous insulin regimens. TRIAL REGISTRATION: clinical trials.gov NCT00377676. [Abstract/Link to Full Text]

Braziuniene I, Wilson TA, Lane AH
Accuracy of self-reported height measurements in parents and its effect on mid-parental target height calculation.
BMC Endocr Disord. 2007;72.
BACKGROUND: Clinical determination of mid-parental height is an important part of the assessment of a child's growth, however our clinical impression has been that parents cannot be relied upon to accurately report their own heights. Therefore, we conducted this study to assess the accuracy of parental height self-reporting and its effect on calculated mid-parental target height for children presenting to a pediatric endocrinology office. METHODS: All parents bringing their children for an initial evaluation to a pediatric endocrinology clinic over a period of nine months were questioned and then measured by a pediatric endocrinologist. Parents were blinded to the study. Mid-parental target heights, based on reported and actual height were compared. RESULTS: There were 241 families: 98 fathers and 217 mothers in our study. Mean measured paternal height was 173.2 cm, self reported 174.9 cm (p < 0.0001), partner reported 177 cm (p = 0.0004). Only 50% of fathers and 58% of mothers reported their height within +/- 2 cm of their measured height, while 15% of fathers and 12% of mothers were inaccurate by more than 4 cm. Mean measured maternal height was 160.6 cm, self-reported 161.1 cm (NS), partner reported 161.7 cm (NS). Inaccuracy of height self-report had a small but significant effect on the mean MPTH (0.4 cm, p = 0.045). Analysis showed that only 70% of MPTH calculated by reported heights fell within +/- 2 cm of MPTH calculated using measured heights, 24% being in +/- 2-4 cm range, and 6% were inaccurate by more than 4 cm. CONCLUSION: There is a significant difference in paternal measured versus reported heights with an overall trend for fathers to overestimate their own height. A large subset of parents makes a substantial error in their height self-report, which leads to erroneous MPTH. Inaccuracy is even greater when one parent reports the other parent's height. When a child's growth is in question, measured rather than reported parental heights should be obtained. [Abstract/Link to Full Text]

Sale MM, Hsu FC, Palmer ND, Gordon CJ, Keene KL, Borgerink HM, Sharma AJ, Bergman RN, Taylor KD, Saad MF, Norris JM
The uncoupling protein 1 gene, UCP1, is expressed in mammalian islet cells and associated with acute insulin response to glucose in African American families from the IRAS Family Study.
BMC Endocr Disord. 2007;71.
BACKGROUND: Variants of uncoupling protein genes UCP1 and UCP2 have been associated with a range of traits. We wished to evaluate contributions of known UCP1 and UCP2 variants to metabolic traits in the Insulin Resistance and Atherosclerosis (IRAS) Family Study. METHODS: We genotyped five promoter or coding single nucleotide polymorphisms (SNPs) in 239 African American (AA) participants and 583 Hispanic participants from San Antonio (SA) and San Luis Valley. Generalized estimating equations using a sandwich estimator of the variance and exchangeable correlation to account for familial correlation were computed for the test of genotypic association, and dominant, additive and recessive models. Tests were adjusted for age, gender and BMI (glucose homeostasis and lipid traits), or age and gender (obesity traits), and empirical P-values estimated using a gene dropping approach. RESULTS: UCP1 A-3826G was associated with AIR(g) in AA (P = 0.006) and approached significance in Hispanic families (P = 0.054); and with HDL-C levels in SA families (P = 0.0004). Although UCP1 expression is reported to be restricted to adipose tissue, RT-PCR indicated that UCP1 is expressed in human pancreas and MIN-6 cells, and immunohistochemistry demonstrated co-localization of UCP1 protein with insulin in human islets. UCP2 A55V was associated with waist circumference (P = 0.045) in AA, and BMI in SA (P = 0.018); and UCP2 G-866A with waist-to-hip ratio in AA (P = 0.016). CONCLUSION: This study suggests a functional variant of UCP1 contributes to the variance of AIR(g) in an AA population; the plausibility of this unexpected association is supported by the novel finding that UCP1 is expressed in islets. [Abstract/Link to Full Text]

Bugalho MJ, Mendonça E, Costa P, Santos JR, Silva E, Catarino AL, Sobrinho LG
A multinodular goiter as the initial presentation of a renal cell carcinoma harbouring a novel VHL mutation.
BMC Endocr Disord. 2006;66.
BACKGROUND: Secondary involvement of the thyroid gland is rare. Often the origin of the tumor is difficult to identify from the material obtained by fine-needle aspiration cytology. Renal cell carcinoma of the clear-cell type is one of the more common carcinomas to metastasize to the thyroid gland. Somatic mutations of the von Hippel-Lindau tumor suppressor gene are associated with the sporadic form of this tumor. We aimed to illustrate the potential utility of DNA based technologies to search for specific molecular markers in order to establish the anatomic site of origin. CASE PRESENTATION: A 54-yr-old Caucasian male complaining of a rapidly increasing neck tumor was diagnosed as having a clear-cell tumor by fine-needle aspiration cytology. A positive staining for cytokeratin as well as for vimentin and CD10 in the absence of staining for thyroglobulin, calcitonin and TTF1 suggested a renal origin confirmed by computed tomography.Using frozen RNA, obtained from cells left inside the needle used for fine needle aspiration cytology, it was possible to identify a somatic mutation (680 delA) in the VHL gene. CONCLUSION: In the presence of a clear-cell tumor of the thyroid gland, screening for somatic mutations in the VHL gene in material derived from thyroid aspirates might provide additional information to immunocytochemical studies and therefore plays a contributory role to establish the final diagnosis. Moreover, in a near future, this piece of information might be useful to define a targeted therapy. [Abstract/Link to Full Text]

Dumas H, Panayiotopoulos P, Parker D, Pongpairochana V
Understanding and meeting the needs of those using growth hormone injection devices.
BMC Endocr Disord. 2006;65.
BACKGROUND: Recombinant human growth hormone (r-hGH) is used to treat: growth hormone deficiency in children and adults; children born small for gestational age; Turner's syndrome; and chronic renal failure. r-hGH is administered by daily subcutaneous injection and may be given using a number of different administration devices. The aim of this survey was, firstly, to identify which attributes of an r-hGH administration device are considered most important to physicians, teenage patients, parents of young children requiring GH and nurses who have experience of r-hGH administration, and, secondly, to determine how they rate existing devices in each of these key attributes. METHODS: The opinions of 67 individuals with experience in r-hGH administration were captured in discussion sessions. Parents, physicians and nurses were asked to rate 19 device attributes by completing a questionnaire, and to rank four different r-hGH administration devices (including a conceptual electronic device) in order of preference. RESULTS: Reliability, ease of use, lack of pain during injection, safety in use, storage, and number of steps in preparation before use, during use and after were considered to be the five most desirable attributes of an r-hGH administration device. An electronic device was preferred to an automatic, multi-dose injection device, a needle-free injection device or a manual, ready-to-use, disposable injection device. CONCLUSION: In the opinion of physicians, nurses and parents using r-hGH injection devices, an ideal device must combine reliability with simplicity, while delivering treatment with minimal pain. An electronic device, which combines many of the most useful features of existing devices with novel functions, was the preferred option for r-hGH administration. [Abstract/Link to Full Text]

Onady GM, Langdon LJ
Insulin versus oral agents in the management of Cystic Fibrosis Related Diabetes: a case based study.
BMC Endocr Disord. 2006;64.
BACKGROUND: Insulin is the recommend therapeutic agent of choice for the management of Cystic Fibrosis Related Diabetes (CFRD), despite only sub-optimal reductions in glycemic control and increased morbidity and mortality reported by centers using this agent. The newer insulin sensitizing agents demonstrated to have anti-inflammatory mechanisms may provide an alternative management option for CFRD. METHODS: A prospective case based therapeutic comparison between insulin, sulfonylurea, metformin and thiazolidinedione was observed over one decade with 20 CFRD patients diagnosed using American Diabetes Association guideline standards. Patients entering the study elected treatment based on risk and benefit information provided for treatment options. Patients receiving organ transplant or requiring combination diabetic medications were excluded from the study. RESULTS: No statistical advantage was achieved regarding overall glycemic control for oral agents over insulin. Additional outcome measures including changes in weight, liver function testing and FEV1 were not statistically significant. CONCLUSION: Insulin alone may not be the only therapeutic option in managing CFRD. Oral hypoglycemic agents were equally effective in treating CFRD and may provide an alternative class of agents for patients reluctant in using insulin. [Abstract/Link to Full Text]

Tran HA
Reversible hypothyroidism and Whipple's disease.
BMC Endocr Disord. 2006;63.
BACKGROUND: The major cause of primary hypothyroidism is autoimmune mediated with progressive and permanent destruction of the thyroid gland resulting in life-long replacement therapy. Treatable and reversible hypothyroidism is unusual and here forth is such a case due to infection of the thyroid gland with Tropheryma whippleii, Whipple disease. CASE PRESENTATION: A 45 year-old female presented with symptoms and signs consistent with primary hypothyroidism, which was also confirmed biochemically. Her response to thyroxine replacement therapy was poor however, requiring a significantly elevated amount. Further investigation revealed the presence of Whipple's disease involving the gastrointestinal trace and possibly the thyroid gland. Her thyroxine requirement decreased drastically following appropriate antimicrobial therapy for Whipple's disease to the extent that it was ceased. Thyrotropin releasing hormone testing in the steady state suggested there was diminished thyroid reserve due to Whipple's disease. CONCLUSION: This is the first ante-mortem case report studying the possible involvement of the thyroid gland by Whipple's disease. Despite the normalization of her thyroid function test biochemically after antibiotic therapy, there is diminished thyroid reserve thus requiring close and regular monitoring. [Abstract/Link to Full Text]

Aijaz NJ, Flaherty EM, Preston T, Bracken SS, Lane AH, Wilson TA
Neurocognitive function in children with compensated hypothyroidism: lack of short term effects on or off thyroxin.
BMC Endocr Disord. 2006;62.
BACKGROUND: Although thyroxin therapy clearly is beneficial to children with frank hypothyroidism there is little data on the effects of thyroxin in children with compensated or subclinical hypothyroidism. The objective of this study was to determine the effect of thyroxin therapy on cognitive function in children with compensated hypothyroidism. The hypothesis was that thyroxin therapy would change neuropsychological function. METHODS: Eleven patients with a history of sub clinical hypothyroidism entered the study. At the start of the study, six out of the 11 were on thyroxin therapy, while 5 were off therapy. All patients underwent a battery of neuropsychological testing and thyroid function tests at the start of study. Based on the results of thyroid function tests, two of the 5 patients who were off thyroxin were started back on thyroxin. All of the 6 patients who were on thyroxin were taken off thyroxin. All patients then underwent repeat neuropsychological testing and thyroid functions after an average of 91 days. RESULTS: Thyroxin therapy could not be shown to have an effect on neuropsychological function in this short term study. Our patients had attention problems as compared to the normal population. No significant differences were found between our subjects and normal population standards in verbal processing, visual processing, motor speed/coordination and achievement. CONCLUSION: In this small, short term study, thyroxin therapy could not be shown to affect neuropsychological function in children with compensated hypothyroidism. These children may have attention problems but appear to have normal verbal and visual processing, motor speed/coordination and achievement. [Abstract/Link to Full Text]

de Gregorio C, Curtò L, Recupero A, Grimaldi P, Almoto B, Venturino M, Cento D, Narbone MC, Trimarchi F, Coglitore S, Cannavò S
Echocardiographic assessment of subclinical left ventricular eccentric hypertrophy in adult-onset GHD patients by geometric remodeling: an observational case-control study.
BMC Endocr Disord. 2006;61.
BACKGROUND: Most patients with growth hormone deficiency (GHD) show high body mass index. Overweight subjects, but GHD patients, were demonstrated to have high left ventricular mass index (LVMi) and abnormal LV geometric remodeling. We sought to study these characteristics in a group of GHD patients, in an attempt to establish the BMI-independent role of GHD. METHODS: Fifty-four patients, 28 F and 26 M, aged 45.9 +/- 13.1, with adult-onset GHD (pituitary adenomas 48.2%, empty sella 27.8%, pituitary inflammation 5.5%, cranio-pharyngioma 3.7%, not identified pathogenesis 14.8%) were enrolled. To minimize any possible interferences of BMI on the aim of this study, the control group included 20 age- and weight-matched healthy subjects. The LV geometry was identified by the relationship between LVMi (cut-off 125 g/m2) and relative wall thickness (cut-off 0.45) at echocardiography. RESULTS: There was no significant between-group difference in resting cardiac morphology and function, nor when considering age-related discrepancy. The majority of patients had normal-low LVM/LVMi, but about one fourth of them showed higher values. These findings correlated to relatively high circulating IGF-1 and systolic blood pressure at rest. The main LV geometric pattern was eccentric hypertrophy in 22% of GHD population (26% of with severe GHD) and in 15% of controls (p = NS). CONCLUSION: Though the lack of significant differences in resting LV morphology and function, about 25% of GHD patients showed high LVMi (consisting of eccentric hypertrophy), not dissimilarly to overweight controls. This finding, which prognostic role is well known in obese and hypertensive patients, is worthy to be investigated in GHD patients through wider controlled trials. [Abstract/Link to Full Text]

Jönsson T, Olsson S, Ahrén B, Bøg-Hansen TC, Dole A, Lindeberg S
Agrarian diet and diseases of affluence--do evolutionary novel dietary lectins cause leptin resistance?
BMC Endocr Disord. 2005;510.
BACKGROUND: The global pattern of varying prevalence of diseases of affluence, such as obesity, cardiovascular disease and diabetes, suggests that some environmental factor specific to agrarian societies could initiate these diseases. PRESENTATION OF THE HYPOTHESIS: We propose that a cereal-based diet could be such an environmental factor. Through previous studies in archaeology and molecular evolution we conclude that humans and the human leptin system are not specifically adapted to a cereal-based diet, and that leptin resistance associated with diseases of affluence could be a sign of insufficient adaptation to such a diet. We further propose lectins as a cereal constituent with sufficient properties to cause leptin resistance, either through effects on metabolism central to the proper functions of the leptin system, and/or directly through binding to human leptin or human leptin receptor, thereby affecting the function. TESTING THE HYPOTHESIS: Dietary interventions should compare effects of agrarian and non-agrarian diets on incidence of diseases of affluence, related risk factors and leptin resistance. A non-significant (p = 0.10) increase of cardiovascular mortality was noted in patients advised to eat more whole-grain cereals. Our lab conducted a study on 24 domestic pigs in which a cereal-free hunter-gatherer diet promoted significantly higher insulin sensitivity, lower diastolic blood pressure and lower C-reactive protein as compared to a cereal-based swine feed. Testing should also evaluate the effects of grass lectins on the leptin system in vivo by diet interventions, and in vitro in various leptin and leptin receptor models. Our group currently conducts such studies. IMPLICATIONS OF THE HYPOTHESIS: If an agrarian diet initiates diseases of affluence it should be possible to identify the responsible constituents and modify or remove them so as to make an agrarian diet healthier. [Abstract/Link to Full Text]

Gunawardana SC, Head WS, Piston DW
Amiloride derivatives enhance insulin release in pancreatic islets from diabetic mice.
BMC Endocr Disord. 2005;59.
BACKGROUND: Amiloride derivatives, commonly used for their diuretic and antihypertensive properties, can also cause a sustained but reversible decrease of intracellular pH (pHi). Using dimethyl amiloride (DMA) on normal rodent pancreatic islets, we previously demonstrated the critical influence of islet pHi on insulin secretion. Nutrient-stimulated insulin secretion (NSIS) requires a specific pHi-range, and is dramatically enhanced by forced intracellular acidification with DMA. Furthermore, DMA can enable certain non-secretagogues to stimulate insulin secretion, and induce time-dependent potentiation (TDP) of insulin release in mouse islets where this function is normally absent. The present study was performed to determine whether pHi-manipulation could correct the secretory defect in islets isolated from mice with type 2 diabetes. METHODS: Using two mouse models of type 2 diabetes, we compared a) pHi-regulation, and b) NSIS with and without treatment with amiloride derivatives, in islets isolated from diabetic mice and wild type mice. RESULTS: A majority of the islets from the diabetic mice showed a slightly elevated basal pHi and/or poor recovery from acid/base load. DMA treatment produced a significant increase of NSIS in islets from the diabetic models. DMA also enabled glucose to induce TDP in the islets from diabetic mice, albeit to a lesser degree than in normal islets. CONCLUSION: Islets from diabetic mice show some mis-regulation of intracellular pH, and their secretory capacity is consistently enhanced by DMA/amiloride. Thus, amiloride derivatives show promise as potential therapeutic agents for type 2 diabetes. [Abstract/Link to Full Text]

Tran HA, Jones TL, Batey RG
The spectrum of thyroid dysfunction in an Australian hepatitis C population treated with combination Interferon-alpha2beta and Ribavirin.
BMC Endocr Disord. 2005 Oct 12;58.
BACKGROUND: The study aims to assess the pattern of thyroid response to combination Interferon-alpha2beta (IFN-alpha) and Ribavirin (RBV) anti-viral therapy in an Australian hepatitis C cohort. These include the prevalence of thyroid dysfunction (TD) including hyperthyroidism and hypothyroidism and their possible predictors, the common overall pattern of thyroid function tests whilst receiving therapy and TD outcomes, and the correlation with HCV status outcome. METHODS: A retrospective analysis of all medical records was performed to assess thyroid function in Hepatitis C Virus (HCV) patients who were treated at the Hunter Area hepatitis C treatment center between 1995 and March 2004. The centre is part of the John Hunter hospital, a major tertiary referral centre in New South Wales, Australia. RESULTS: There were 272 cases available for review. The prevalence of TD is 6.7 percent and is made up predominantly of females (80 percent). There were 3 (1.1 percent) cases of hyperthyroidism with 2 (67 percent) females. Thirteen out of fifteen (80 percent) cases of hypothyroidism were females with the overall prevalence of 5.5 percent. The majority of hypothyroid patients still required Thyroxine supplement at the end of follow up. CONCLUSION: Ninety three percent of HCV treated patients have intact thyroid function at the end of treatment. The predominant TD is hypothyroidism. The predominant pattern of thyrotoxicosis (TTX) is that of thyroiditis although the number is small. Graves' like disease was not observed. People with pre-existing thyroid auto-antibodies should be closely monitored for thyroid dysfunction, particularly hypothyroidism. [Abstract/Link to Full Text]

Dixit M, Bhattacharya S, Mittal B
Association of CETP TaqI and APOE polymorphisms with type II diabetes mellitus in North Indians: a case control study.
BMC Endocr Disord. 2005 Jul 1;57.
BACKGROUND: Genetic variants of proteins involved in lipid metabolism may play an important role in determining the susceptibility for complications associated with type II diabetes mellitus (T2DM). Goal of the present study was to determine the association of cholesteryl ester transfer protein TaqI B, D442G, and APOE Hha I polymorphisms with T2DM and its complications. METHODS: Study subjects were 136 patients and 264 healthy controls. All polymorphisms were detected using PCR-RFLP and statistical analysis done with chi2 test and ANOVA. RESULTS: Although CETP TaqI B polymorphism was not associated with the T2DM, yet B1B2 genotype was significantly (p = 0.028) associated with high risk of hypertension in diabetic patients (OR = 3.068, 95% CI 1.183-7.958). In North Indians D442G variation in CETP gene was found to be absent. Frequency of APOE HhaI polymorphism was also not different between patients and controls. In diabetic patients having neuropathy and retinopathy significantly different levels of total-cholesterol [(p = 0.001) and (p = 0.029) respectively] and LDL-cholesterol [(p = 0.001) and (p = 0.001) respectively] were observed when compared to patients with T2DM only. However, lipid levels did not show any correlation with the CETP TaqI B and APOE Hha I genetic polymorphisms. CONCLUSION: CETP TaqI B and APOE HhaI polymorphism may not be associated with type II diabetes mellitus in North Indian population, however CETP TaqI B polymorphism may be associated with hypertension along with T2DM. [Abstract/Link to Full Text]

Fonseca CT, Amaral DM, Ribeiro MG, Beserra IC, Guimarães MM
Insulin resistance in adolescents with Down syndrome: a cross-sectional study.
BMC Endocr Disord. 2005 Jun 17;56.
BACKGROUND: The prevalence of diabetes mellitus is higher in individuals with Down syndrome (DS) than in the general population; it may be due to the high prevalence of obesity presented by many of them. The aim of this study was to evaluate the insulin resistance (IR) using the HOMA (Homeostasis Model Assessment) method, in DS adolescents, describing it according to the sex, body mass index (BMI) and pubertal development. METHODS: 15 adolescents with DS (8 males and 7 females) were studied, aged 10 to 18 years, without history of disease or use of medication that could change the suggested laboratory evaluation. On physical examination, the pubertal signs, acanthosis nigricans (AN), weight and height were evaluated. Fasting plasma glucose and insulin were analysed by the colorimetric method and RIA-kit LINCO, respectively. IR was calculated using the HOMA method. The patients were grouped into obese, overweight and normal, according to their BMI percentiles. The EPIINFO 2004 software was used to calculate the BMI, its percentile and Z score. RESULTS: Five patients were adults (Tanner V or presence of menarche), 9 pubertal (Tanner II-IV) and 1 prepubertal (Tanner I). No one had AN. Two were obese, 4 overweight and 9 normal. Considering the total number of patients, HOMA was 1.7 +/- 1.0, insulin 9.3 +/- 4.8 microU/ml and glucose 74.4 +/- 14.8 mg/dl. The HOMA values were 2.0 +/- 1.0 in females and 1.5 +/- 1.0 in males. Considering the nutritional classification, the values of HOMA and insulin were: HOMA: 3.3 +/- 0.6, 2.0 +/- 1.1 and 1.3 +/- 0.6, and insulin: 18.15 +/- 1.6 microU/ml, 10.3 +/- 3.5 microU/ml and 6.8 +/- 2.8 microU/ml, in the obese, overweight and normal groups respectively. Considering puberty, the values of HOMA and insulin were: HOMA: 2.5 +/- 1.3, 1.4 +/- 0.6 and 0.8 +/- 0.0, and insulin: 13.0 +/- 5.8 microU/ml, 7.8 +/- 2.9 microU/ml and 4.0 +/- 0.0 microU/ml, in the adult, pubertal and prepubertal groups respectively. CONCLUSION: The obese and overweight, female and adult patients showed the highest values of HOMA and insulin. [Abstract/Link to Full Text]

te Velde SJ, van Rossum EF, Voorhoeve PG, Twisk JW, Delemarre van de Waal HA, Stehouwer CD, van Mechelen W, Lamberts SW, Kemper HC
An IGF-I promoter polymorphism modifies the relationships between birth weight and risk factors for cardiovascular disease and diabetes at age 36.
BMC Endocr Disord. 2005 Jun 1;55.
OBJECTIVE: To investigate whether IGF-I promoter polymorphism was associated with birth weight and risk factors for cardiovascular disease (CVD) and type 2 diabetes (T2DM), and whether the birth weight--risk factor relationship was the same for each genotype. DESIGN AND PARTICIPANTS: 264 subjects (mean age 36 years) had data available on birth weight, IGF-I promoter polymorphism genotype, CVD and T2DM risk factors. Student's t-test and regression analyses were applied to analyse differences in birth weight and differences in the birth weight--risk factors relationship between the genotypes. RESULTS: Male variant carriers (VCs) of the IGF-I promoter polymorphism had a 0.2 kg lower birth weight than men with the wild type allele (p = 0.009). Of the risk factors for CVD and T2DM, solely LDL concentration was associated with the genotype for the polymorphism. Most birth weight--risk factor relationships were stronger in the VC subjects; among others the birth weight--systolic blood pressure relationship: 1 kg lower birth weight was related to an 8.0 mmHg higher systolic blood pressure CONCLUSION: The polymorphism in the promoter region of the IGF-I gene is related to birth weight in men only, and to LDL concentration only. Furthermore, the genotype for this polymorphism modified the relationships between birth weight and the risk factors, especially for systolic and diastolic blood pressure. [Abstract/Link to Full Text]

Petrofsky J, Lee S, Cuneo M
Effects of aging and type 2 diabetes on resting and post occlusive hyperemia of the forearm; the impact of rosiglitazone.
BMC Endocr Disord. 2005 Mar 24;5(1):4.
BACKGROUND: Both Diabetes and ageing are associated with reduced vascular endothelial function. The exact relationship between the 2 and any improvements from the insulin sensitizer rosiglitazone have not been explored. METHODS: Thirty controls and sixteen subjects with type 2 diabetes participated in a series of experiments to examine the interrelationships between age, diabetes and endothelial cell function. In subjects with diabetes, the insulin sensitizer rosiglitazone (RSG), a drug also known to improve vascular function, was administered for 3 months to see how it altered these relationships. Resting forearm flows (RF) and blood flows after 4 min of vascular occlusion (PF) were measured as an index of endothelial cell function. RESULTS: RF, measured by venous occlusion plethysmography, was negatively correlated to both age and diabetes. Administration of RSG for 3 months was associated with an increase in the blood flow response to venous occlusion so that it was not significantly different than that of age matched controls. Total PF in control subjects, compared to subjects with diabetes, averaged 56.58 +/- 12.57 and 13.6 +/- 8.01 cc/100 cc tissue per min respectively, and were significantly different (p < 0.01). After 3 months on RSG, differences between PF in the two groups were no longer evident. CONCLUSION: These studies suggest a different mechanism causing a reduction in vascular reactivity with aging and diabetes. [Abstract/Link to Full Text]

Moayyeri A, Soltani A, Tabari NK, Sadatsafavi M, Hossein-Neghad A, Larijani B
Discordance in diagnosis of osteoporosis using spine and hip bone densitometry.
BMC Endocr Disord. 2005 Mar 11;5(1):3.
BACKGROUND: Diagnostic discordance for osteoporosis is the observation that the T-score of an individual patient varies from one key measurement site to another, falling into two different diagnostic categories identified by the World Health Organization (WHO) classification system. This study was conducted to evaluate the presence and risk factors for this phenomenon in a large sample of Iranian population. METHODS: Demographic data, anthropometric measurements, and risk factors for osteoporosis were derived from a database on 4229 patients referred to a community-based outpatient osteoporosis testing center from 2000 to 2003. Dual-energy X-ray absorptiometry (DXA) was performed on L1-L4 lumbar spine and total hip for all cases. Minor discordance was defined as present when the difference between two sites was no more than one WHO diagnostic class. Major discordance was present when one site is osteoporotic and the other is normal. Subjects with incomplete data were excluded. RESULTS: In 4188 participants (3848 female, mean age 53.4 +/- 11.8 years), major discordance, minor discordance, and concordance of T-scores were seen in 2.7%, 38.9% and 58.3%, respectively. In multivariate logistic regression analysis, older age, menopause, obesity, and belated menopause were recognized as risk factors and hormone replacement therapy as a protective factor against T-score discordance. CONCLUSION: The high prevalence of T-score discordance may lead to problems in interpretation of the densitometry results for some patients. This phenomenon should be regarded as a real and prevalent finding and physicians should develop a particular strategy approaching to these patients. [Abstract/Link to Full Text]

Sreemantula S, Kilari EK, Vardhan VA, Jaladi R
Influence of antioxidant (L- ascorbic acid) on tolbutamide induced hypoglycaemia/antihyperglycaemia in normal and diabetic rats.
BMC Endocr Disord. 2005 Mar 3;5(1):2.
BACKGROUND: Diabetes mellitus is a chronic metabolic disorder characterized by hyperglycaemia. Increased oxidative stress and decreased antioxidant levels are the leading cause of diabetes and diabetic complications. So it is felt that supplementation of antioxidants may be useful in controlling the glucose levels and to postpone the occurrence of diabetic complications. The objective of our study is to find the influence of antioxidant supplementation (L-ascorbic acid) on tolbutamide activity in normal and diabetic rats. METHODS: L- ascorbic acid/tolbutamide/L-ascorbic acid + tolbutamide were administered orally to 3 different groups of albino rats of either sex in normal and diabetic condition. Blood samples were collected from retro-orbital puncture at different time intervals and were analyzed for blood glucose by GOD-POD method. Diabetes was induced by alloxan 100 mg/kg body weight administered by I.P route. RESULTS: L-ascorbic acid/ tolbutamide produced hypoglycaemic activity in a dose dependant manner in normal and diabetic condition. In the presence of L-ascorbic acid, tolbuatmide produced early onset of action and maintained for longer period compared to tolbutamide matching control. CONCLUSION: Supplementation of antioxidants like L-ascorbic acid was found to improve tolbutamide response in normal and diabetic rats. [Abstract/Link to Full Text]

Sawka AM, Thabane L, Gafni A, Levine M, Young WF
Measurement of fractionated plasma metanephrines for exclusion of pheochromocytoma: Can specificity be improved by adjustment for age?
BMC Endocr Disord. 2005 Feb 28;5(1):1.
BACKGROUND: Biochemical testing for pheochromocytoma by measurement of fractionated plasma metanephrines is limited by false positive rates of up to 18% in people without known genetic predisposition to the disease. The plasma normetanephrine fraction is responsible for most false positives and plasma normetanephrine increases with age. The objective of this study was to determine if we could improve the specificity of fractionated plasma measurements, by statistically adjusting for age. METHODS: An age-adjusted metanephrine score was derived using logistic regression from 343 subjects (including 33 people with pheochromocytoma) who underwent fractionated plasma metanephrine measurements as part of investigations for suspected pheochromocytoma at Mayo Clinic Rochester (derivation set). The performance of the age-adjusted score was validated in a dataset of 158 subjects (including patients 23 with pheochromocytoma) that underwent measurements of fractionated plasma metanephrines at Mayo Clinic the following year (validation dataset). None of the participants in the validation dataset had known genetic predisposition to pheochromocytoma. RESULTS: The sensitivity of the age-adjusted metanephrine score was the same as that of traditional interpretation of fractionated plasma metanephrine measurements, yielding a sensitivity of 100% (23/23, 95% confidence interval [CI] 85.7%, 100%). However, the false positive rate with traditional interpretation of fractionated plasma metanephrine measurements was 16.3% (22/135, 95% CI, 11.0%, 23.4%) and that of the age-adjusted score was significantly lower at 3.0% (4/135, 95% CI, 1.2%, 7.4%) (p < 0.001 using McNemar's test). CONCLUSION: An adjustment for age in the interpretation of results of fractionated plasma metanephrines may significantly decrease false positives when using this test to exclude sporadic pheochromocytoma. Such improvements in false positive rate may result in savings of expenditures related to confirmatory imaging. [Abstract/Link to Full Text]

Alavian SM, Hajarizadeh B, Nematizadeh F, Larijani B
Prevalence and determinants of diabetes mellitus among Iranian patients with chronic liver disease.
BMC Endocr Disord. 2004 Nov 19;4(1):4.
BACKGROUND: Alterations in carbohydrate metabolism are frequently observed in cirrhosis. We conducted this study to define the prevalence of diabetes mellitus (DM) and impaired glucose tolerance (IGT) in Iranian patients with chronic liver disease (CLD), and explore the factors associated with DM in these patients. METHODS: One hundred and eighty-five patients with CLD were enrolled into the study. Fasting plasma glucose and two-hour plasma glucose were measured in patients' sera. DM and IGT were diagnosed according to the latest American Diabetes Association criteria. RESULTS: The subjects included 42 inactive HBV carriers with a mean age of 42.2 +/- 12.0 years, 102 patients with HBV or HCV chronic hepatitis with a mean age of 41.2 +/- 10.9 years, and 41 cirrhotic patients with a mean age of 52.1 +/- 11.4 years. DM and IGT were diagnosed in 40 (21.6%) and 21 (11.4%) patients, respectively. Univariate analysis showed that age (P = 0.000), CLD status (P = 0.000), history of hypertension (P = 0.007), family history of DM (P = 0.000), and body mass index (BMI) (P = 0.009) were associated with DM. Using Multivariate analysis, age (OR = 4.7, 95%CI: 1.8-12.2), family history of DM (OR = 6.6, 95%CI: 2.6-17.6), chronic hepatitis (OR = 11.6, 95%CI: 2.9-45.4), and cirrhosis (OR = 6.5, 95%CI: 2.4-17.4) remained as the factors independently associated with DM. When patients with cirrhosis and chronic hepatitis were analyzed separately, higher Child-Pugh's score in cirrhotic patients (OR = 9.6, 95%CI: 1.0-88.4) and older age (OR = 7.2, 95%CI: 1.0-49.1), higher fibrosis score (OR = 59.5, 95%CI: 2.9-1211.3/ OR = 11.9, 95%CI: 1.0-132.2), and higher BMI (OR = 30.3, 95%CI: 3.0-306.7) in patients with chronic hepatitis were found to be associated with higher prevalence of DM. CONCLUSIONS: Our findings indicate that patients with cirrhosis and chronic hepatitis are at the increased risk of DM occurrence. Older age, severe liver disease, and obesity were associated with DM in these patients. [Abstract/Link to Full Text]

Barbosa AS, Giacaglia LR, Martin RM, Mendonca BB, Lin CJ
Assessment of the role of transcript for GATA-4 as a marker of unfavorable outcome in human adrenocortical neoplasms.
BMC Endocr Disord. 2004 Jul 7;4(1):3.
BACKGROUND: Malignant neoplasia of the adrenal cortex is usually associated with very poor prognosis. When adrenocortical neoplasms are diagnosed in the early stages, distinction between carcinoma and adenoma can be very difficult to accomplish, since there is yet no reliable marker to predict tumor recurrence or dissemination. GATA transcription factors play an essential role in the developmental control of cell fate, cell proliferation and differentiation, organ morphogenesis, and tissue-specific gene expression. Normal mouse adrenal cortex expresses GATA-6 while its malignant counterpart only expresses GATA-4. The goal of the present study was to assess whether this reciprocal change in the expression of GATA factors might be relevant for predicting the prognosis of human adrenocortical neoplasms. Since human adrenal cortices express luteinizing hormone (LH/hCG) receptor and the gonadotropins are known to up-regulate GATA-4 in gonadal tumor cell lines, we also studied the expression of LH/hCG receptor. METHODS: We conducted a study on 13 non-metastasizing (NM) and 10 metastasizing/recurrent (MR) tumors obtained from a group of twenty-two adult and pediatric patients. The expression of GATA-4, GATA-6, and LH/hCG receptor (LHR) in normal and tumoral human adrenal cortices was analysed using reverse transcriptase-polymerase chain reaction (RT-PCR) complemented by dot blot hybridization. RESULTS: Messenger RNA for GATA-6 was detected in normal adrenal tissue, as well as in the totality of NM and MR tumors. GATA-4, by its turn, was detected in normal adrenal tissue, in 11 out of 13 NM tumors, and in 9 of the 10 MR tumors, with larger amounts of mRNA found among those presenting aggressive clinical behavior. Transcripts for LH receptor were observed both in normal tissue and neoplasms. A more intense LHR transcript accumulation was observed on those tumors with better clinical outcome. CONCLUSION: Our data suggest that the expression of GATA-6 in human adrenal cortex is not affected by tumorigenesis. GATA-4 expression is more abundant in MR tumors, while NM tumors express more intensely LHR. Further studies with larger cohorts are needed to test whether relative expression levels of LHR or GATA-4 might be used as prognosis predictors. [Abstract/Link to Full Text]

Sawka AM, Prebtani AP, Thabane L, Gafni A, Levine M, Young WF
A systematic review of the literature examining the diagnostic efficacy of measurement of fractionated plasma free metanephrines in the biochemical diagnosis of pheochromocytoma.
BMC Endocr Disord. 2004 Jun 29;4(1):2.
BACKGROUND: Fractionated plasma metanephrine measurements are commonly used in biochemical testing in search of pheochromocytoma. METHODS: We aimed to critically appraise the diagnostic efficacy of fractionated plasma free metanephrine measurements in detecting pheochromocytoma. Nine electronic databases, meeting abstracts, and the Science Citation Index were searched and supplemented with previously unpublished data. Methodologic and reporting quality was independently assessed by two endocrinologists using a checklist developed by the Standards for Reporting of Diagnostic Studies Accuracy Group and data were independently abstracted. RESULTS: Limitations in methodologic quality were noted in all studies. In all subjects (including those with genetic predisposition): the sensitivities for detection of pheochromocytoma were 96%-100% (95% CI ranged from 82% to 100%), whereas the specificities were 85%-100% (95% CI ranged from 78% to 100%). Statistical heterogeneity was noted upon pooling positive likelihood ratios when those with predisposition to disease were included (p < 0.001). However, upon pooling the positive or negative likelihood ratios for patients with sporadic pheochromocytoma (n = 191) or those at risk for sporadic pheochromocytoma (n = 718), no statistical heterogeneity was noted (p = 0.4). For sporadic subjects, the pooled positive likelihood ratio was 5.77 (95% CI = 4.90, 6.81) and the pooled negative likelihood ratio was 0.02 (95% CI = 0.01, 0.07). CONCLUSION: Negative plasma fractionated free metanephrine measurements are effective in ruling out pheochromocytoma. However, a positive test result only moderately increases suspicion of disease, particularly when screening for sporadic pheochromocytoma. [Abstract/Link to Full Text]

Gunawardana SC, Rocheleau JV, Head WS, Piston DW
Nutrient-stimulated insulin secretion in mouse islets is critically dependent on intracellular pH.
BMC Endocr Disord. 2004 Jun 11;4(1):1.
BACKGROUND: Many mechanistic steps underlying nutrient-stimulated insulin secretion (NSIS) are poorly understood. The influence of intracellular pH (pHi) on insulin secretion is widely documented, and can be used as an investigative tool. This study demonstrates previously unknown effects of pHi-alteration on insulin secretion in mouse islets, which may be utilized to correct defects in insulin secretion. METHODS: Different components of insulin secretion in mouse islets were monitored in the presence and absence of forced changes in pHi. The parameters measured included time-dependent potentiation of insulin secretion by glucose, and direct insulin secretion by different mitochondrial and non-mitochondrial secretagogues. Islet pHi was altered using amiloride, removal of medium Cl-, and changing medium pH. Resulting changes in islet pHi were monitored by confocal microscopy using a pH-sensitive fluorescent indicator. To investigate the underlying mechanisms of the effects of pHi-alteration, cellular NAD(P)H levels were measured using two-photon excitation microscopy (TPEM). Data were analyzed using Student's t test. RESULTS: Time-dependent potentiation, a function normally absent in mouse islets, can be unmasked by a forced decrease in pHi. The optimal range of pHi for NSIS is 6.4-6.8. Bringing islet pHi to this range enhances insulin secretion by all mitochondrial fuels tested, reverses the inhibition of glucose-stimulated insulin secretion (GSIS) by mitochondrial inhibitors, and is associated with increased levels of cellular NAD(P)H. CONCLUSIONS: Pharmacological alteration of pHi is a potential means to correct the secretory defect in non-insulin dependent diabetes mellitus (NIDDM), since forcing islet pHi to the optimal range enhances NSIS and induces secretory functions that are normally absent. [Abstract/Link to Full Text]

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Recent Articles in Endocrine Journal

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Kanazawa I, Yamamoto M, Yamaguchi T, Yamauchi M, Yano S, Sugimoto T
A case of magnesium deficiency associated with insufficient parathyroid hormone action and severe osteoporosis.
Endocr J. 2007 Nov 30; .
The relationship between osteoporosis and magnesium (Mg) deficiency is still controversial. Here we report a case of an 82-year-old woman with a giant adenomatous goiter and severe osteoporosis with multiple vertebral fractures, whose clinical course indicated that her osteoporosis was probably due to Mg deficiency. She visited our hospital for treatments of tetany. Laboratory data showed the existence of hypomagnesemia, hypocalcemia, hypokalemia, vitamin D deficiency, and slightly elevated intact PTH. Intravenous administration of Mg not only improved these electrolyte abnormalities but also increased serum levels of intact PTH, bone formation markers, 1,25-dihydroxyvitamin D, as well as bone resorption markers in the urine, and lowered urinary phosphate reabsorption. Hypomagnesemia on admission seemed to arise from long-lasting poor food intake and malnutrition, because it improved after the disappearance of dysphagia with a goiter resection. After the operation, BMD values at the lumbar spine and femoral neck obviously increased during 6 months of Mg supplementation without any specific therapies for osteoporosis. Mg deficiency in this case seemed to cause impaired secretion of PTH from the parathyroid and the refractoriness of bone and kidney to the hormone, which led to the suppression of both bone remodeling and renal vitamin D production. These processes were probably linked to her severe osteoporosis, which was reversed by Mg supplementation. [Abstract/Link to Full Text]

Yeo KF, Yang YS, Chen KS, Peng CH, Huang CN
Simultaneous Presentation of Thyrotoxicosis and Diabetic Ketoacidosis Resulted in Sudden Cardiac Arrest.
Endocr J. 2007 Nov 30;
Although many cases of simultaneous presentation of thyrotoxicosis (thyroid storm) and diabetic ketoacidosis have been reported, it is a clinically unusual situation and remains a diagnostic and management challenge in clinical practice. The diagnosis of diabetic ketoacidosis or thyrotoxicosis may be masked leading to serious complications. We report two patients with simultaneous thyrotoxicosis and diabetic ketoacidosis resulted in sudden cardiac arrest, emphasizing early recognition and prompt treatment when thes tow disease are presented concomitantly. [Abstract/Link to Full Text]

Aoki K, Kato H, Terauchi Y
Divided-Dose Administration of Miglitol Just Before and 15 Minutes After the Start of a Meal Smoothes Postprandial Plasma Glucose Excursions and Serum Insulin Responses in Healthy Men.
Endocr J. 2007 Nov 30;
We recently demonstrated that administration of miglitol at 15 min after the start of a meal decreased the area under the curve (AUC) of plasma glucose, similar to the observation following its administration just before a meal. This finding prompted us to examine whether a divided-dose regimen of miglitol might attenuate postprandial glucose excursions even more effectively. We, therefore, examined several schedules of miglitol administration in 15 healthy men. Miglitol was administered by four different schedules in each subject (control: no miglitol, intake 1: drug administered just before a meal (50 mg); intake 2: drug administered at 15 min after the start of a meal (50 mg); intake 3: drug administered in two divided doses: just before a meal (25 mg) and at 15 min after the start of a meal (25 mg). The AUC of glucose excursions, defined as increment above the fasting glucose level, (AUC(0-180min) glucose excursion) was significantly reduced as compared with that in the control condition after miglitol administration by intake schedule 3, while this parameter showed a tendency towards decrease after the drug administration by intake schedules 1 and 2. The AUC(0-180min) of the serum insulin level was also significantly decreased for all the intake schedules of miglitol, as compared with that in the control condition. Thus, administration of miglitol in two divided doses appeared to be the most suitable for obtaining effective regulation of postprandial glucose excursions in healthy men. This result may suggest that the divided-dose administration regimen may also be effective in diabetic patients. [Abstract/Link to Full Text]

Shinagawa T, Horikawa R, Isojima T, Naiki Y, Tanaka T, Katsumata N
Nonclassic Steroid 21-Hydroxylase Deficiency Due to a Homozygous V281L Mutation in CYP21A2 Detected by the Neonatal Mass-Screening Program in Japan.
Endocr J. 2007 Nov 30;
Since 1989, neonatal mass screening for congenital adrenal hyperplasia (CAH) has been carried out in Japan. The mass screening has detected not only the patients with the classic form of steroid 21-hydroxylase deficiency (21-OHD), but also those with the nonclassic (NC) form of 21-OHD, and the molecular basis in these patients has been elucidated. However, the homozygous V281L mutation in CYP21A2, the common mutation in the NC form in Caucasians, has not been described in Japanese patients, implying at least two possibilities; 1) the V281L mutation itself might be very rare in Japanese, and 2) nonclassic 21-OHD patients bearing the V281L mutation might be barely detectable by the mass-screening program, hence overlooked in Japan. In the present study, we describe a Brazilian girl with the NC form of 21-OHD, who was pointed out to have mildly elevated 17alpha-hydroxyprogesterone in blood by the mass screening in Japan. Genetic analysis revealed that the patient was homozygous for the V281L mutation, and that the parents were heterozygous for the V281L mutation. Thus, the NC patients due to the homozygous V281L mutation can be detectable by the mass-screening program for CAH in Japan, and further accumulation and analysis of the NC patients should elucidate the frequency of the V281 allele in Japan. [Abstract/Link to Full Text]

Ueno H, Shiiya T, Mizuta M, Mondal MS, Nakazato M
Plasma Ghrelin Concentrations in Different Clinical Stages of Diabetic Complications and Glycemic Control in Japanese Diabetics.
Endocr J. 2007 Nov 16;
Ghrelin is an acylated 28-amino-acid peptide that stimulates food intake, GH secretion, and gastric motility. Experimental studies have suggested that ghrelin plays roles in glucose homeostasis, atherosclerosis, and microangiopathy. We investigated possible involvement of ghrelin in micro- and macro-vascular diabetic complications and glycemic control in diabetic patients. Fasting and postprandial plasma ghrelin concentrations after a test meal were measured in 108 and 61 Japanese diabetic patients, respectively. Plasma ghrelin concentrations were negatively correlated with body mass index (BMI) (r = -0.309, P = 0.002) or HbA(1c) (r = -0.264, P = 0.0065). Plasma ghrelin levels in patients with diabetic nephropathy who showed high serum creatinine levels (s-Cre) were significantly higher than those in patients who showed normal s-Cre (P <0.02). In patients with diabetic triopathy, plasma ghrelin concentrations were significantly lower than those in patients without diabetic complications (P <0.05). Stepwise multiple regression analyses revealed that s-Cre, BMI, and HbA(1c) were independently associated with plasma ghrelin levels. A postprandial decrease of ghrelin was observed in patients with normal CV(R-R) values or those with normal body weight, whereas it was not seen in obese patients or in patients with low CV(R-R) values. Suppression rates of ghrelin 30-60 min after a test meal in obese patients were significantly lower than those in normal-weight patients. These findings suggest that ghrelin secretion is suppressed by long-term hyperglycemia and that obesity influences the regulation of ghrelin secretion. [Abstract/Link to Full Text]

Asano T, Yoshida R, Ogata H, Kokawa K, Ogimoto M, Akehi Y, Anzai K, Ono J, Tamura K, Hidehira K, Kikuchi M
beta-Cell Function is a Major Contributor to Oral Glucose Disposition in Obese Japanese Students.
Endocr J. 2007 Nov 16;
Determinants of glucose intolerance were studied in 163 obese Japanese young adults, 18 to 21 years old (43 females,120 males), who underwent 75-g oral glucose tolerance testing. Type 2 diabetes was newly diagnosed in 2.9% (n=4); impaired fasting glucose (IFG) in 5.1% (n=7); and impaired glucose tolerance (IGT) in 10.9% (n=15). A homeostasis model assessment of insulin resistance (HOMA-IR) was used to estimate insulin sensitivity; beta-cell function during the first 30 min of the test was measured and defined as the insulinogenic index. This index was adjusted for insulin sensitivity, since this affects both beta-cell function and glucose disposition (disposition index). The relationship between insulinogenic index and 1/HOMA-IR was not hyperbolic. However, the disposition index (DI) was useful for the estimation of beta-cell function with the correct confirmation about it validity using beta-cell function index (BI). The association between insulin sensitivity and beta-cell function to glucose disposal, as measured by the area under the glucose curve (AUCg), was examined in all subjects. Insulin sensitivity was significantly related to AUCg (log HOMA-IR; R (2) =0.142, p<0.0001). On the other hand, an inverse curvilinear relationship was observed between beta-cell function and AUCg (log(DeltaI/DeltaG)/HOMA-IR, R (2) =0.411, p<0.0001). Thus, impaired beta-cell function, when estimated as DI, was strongly associated with impaired glucose disposal. In conclusion, our study showed that both insulin sensitivity and impaired beta-cell function are associated with impaired glucose metabolism, and that beta-cell function may be more important in determining glucose disposal. [Abstract/Link to Full Text]

Kuwajima M, Fujihara H, Sei H, Umehara A, Sei M, Tsuda TT, Sukeno A, Okamoto T, Inubushi A, Ueta Y, Doi T, Kido H
Reduced Carnitine Level Causes Death from Hypoglycemia: Possible Involvement of Suppression of Hypothalamic Orexin Expression During Weaning Period.
Endocr J. 2007 Nov 16;
The mechanism of onset of hypoglycemia in patients with carnitine deficiency has yet to be determined. Using mice with systemic carnitine deficiency (JVS mice), we examined this mechanism, focusing on the weaning period (days 14-28 postpartum). For normal mice, the survival rate was 100%, and no hypoglycemia was observed at all. Gastric lactose began to decrease on day 17, and cellulose increased sharply in amount thereafter. For JVS mice, the survival rate was 77% on day 14 and 28% on day 28. From day 21 on, hypoglycemia was noted. Gastric lactose had disappeared almost completely by day 17, and cellulose was almost undetectable from days 14 to 28. Expression of orexin mRNA in the hypothalamus did not differ between JVS and normal mice on day 14, but was suppressed in JVS mice on days 21 and 28. When JVS mice were fed a carnitine-rich diet, suppression of expression of orexin mRNA in hypothalamus was eliminated, and on day 28 lactose and cellulose were detected in the stomach without hypoglycemia. In conclusion, the suppression of the expression of orexin in the hypothalamus during the weaning period may be involved in the marked anorexia in JVS mice, which eventually leads to death from hypoglycemia. [Abstract/Link to Full Text]

Nishihara E, Nagayama Y, Amino N, Hishinuma A, Takano T, Yoshida H, Kubota S, Fukata S, Kuma K, Miyauchi A
A Novel Thyrotropin Receptor Germline Mutation (Asp617Tyr) Causing Hereditary Hyperthyroidism.
Endocr J. 2007 Nov 16;
Constitutively activating germline mutations of the thyrotropin receptor (TSHR) gene have been identified as a molecular cause of hereditary nonautoimmune hyperthyroidism. We describe here a Japanese kindred with two affected individuals who showed overt hyperthyroidism and mild goiter in the absence of TSHR antibodies. A novel heterozygous germline point mutation, identified in both individuals, resulted in an amino acid substitution of aspartic acid for tyrosine at codon 617 (Asp617Tyr) in the third intracellular loop of the TSHR. Screening of 7 additional family members led to the identification of the same mutation in 4 relatives: 1 had undergone thyroidectomy due to hyperthyroidism but 3 were asymptomatic with subclinical hyperthyroidism. In vitro functional studies of the Asp617Tyr TSHR demonstrated a constitutive activation of the cyclic adenosine monophosphate pathway, but not of the inositol phosphate cascade, with data similar to those of Asp619Gly, the first constitutively activating mutant TSHR identified. Treatment with inorganic iodine for 7 months successfully relieved all symptoms of hyperthyroidism in both patients. [Abstract/Link to Full Text]

Ogo A, Eto T, Hiramatsu S, Watanabe A, Sakai Y, Yoshizumi H, Uesugi N, Nakajima O
Autopsy of a Patient with Cushing's Syndrome Who Was Revealed to Have Pulmonary Tumorlets Producing Ectopic ACTH.
Endocr J. 2007 Nov 14;
The patient, a 78-year-old female with a 10-year history of type 2 diabetes mellitus, was admitted to our department for evaluation of leg edema and general fatigue. Biochemical investigations revealed hypokalemia and elevated serum cortisol and plasma ACTH levels, with a loss of diurnal rhythm and failure of suppression at high doses (8 mg) of dexamethasone. No pituitary tumor or parasellar tumor was detected by contrast-enhanced computed tomography (CT) or magnetic resonance image scan of the pituitary. High resolution CT of the lung and bronchoscopic examination revealed no abnormalities. Abdominal and pelvic CT indicated bilateral, slightly diffuse, adrenal gland hyperplasia only. These findings led to a diagnosis of ACTH-dependent hypercortisolism from an undefined source. Ten days after admission the patient had a fever and was diagnosed with disseminated intravascular coagulation. Despite intensive treatment about 1 month after admission the patient died from progressive multiple organ failure. At autopsy, a histological examination of the periphery of the right middle lobe of the lung revealed the presence of tumorlets. Immunohistochemical staining of the tumorlets revealed scattered cells containing ACTH and many cells containing chromogranin A that were positive for Grimelius staining. In addition, multiple microabscesses were present throughout most tissues of the body. The ectopic hormonal production observed in the present case suggests that pulmonary tumorlets should thus be considered in the differential diagnosis of Cushing's syndrome, and medical treatment to inhibit steroidogenesis should be started immediately to reduce the risk of complications from hypercortisolism. [Abstract/Link to Full Text]

Tajima T, Fujiwara F, Sudo A, Saito S, Fujieda K
A Japanese patient of congenital hypothyroidism with cerebellar atrophy.
Endocr J. 2007 Nov 14;
We encountered a Japanese patient of congenital hypothyroidism with severe cerebellum atrophy. The boy was born after 40 weeks of gestation by normal vaginal delivery from nonconsanguineous parents. There were no abnormal physical findings; however neonatal mass screening for congenital hypothyroidism at 5 days of age demonstrated elevated thyrotropin (TSH) level (15.5 muU/ml, normal range 0.54-10.0 muU/ml). He was suspected to have subclinical or mild congenital hypothyroidism (CH). Thus he was treated with L-thyroxine using a regimen that rendered his serum TSH concentration within normal range from 27 days of age. Despite early and adequate treatment, he showed signs of global developmental delay and became gradually hypotonic and exhibited a staggering gait at 3 years of age. Brain magnetic resonance imaging (MRI) demonstrated marked cerebellar atrophy with an intact brainstem. Thyroidal uptake of radioiodide and thyroid gland size were normal, indicating a functional defect only. The relation between congenital hypothyroidism and severe cerebellar atrophy in our patient is not clear. As only a few cases of the combination of CH and cerebellar anomalies have been described previously, cerebellar symptoms in CH should be examined carefully. [Abstract/Link to Full Text]

Mise H, Yura S, Itoh H, Nuama MA, Takemura M, Sagawa N, Fujii S
The Relationship between Maternal Plasma Leptin Levels and Fetal Growth Restriction.
Endocr J. 2007 Nov 14;
Leptin is a satiety hormone secreted from the adipose tissue and human placenta. We previously demonstrated that severe preeclampsia up-regulated leptin mRNA expression in the placenta and elevated maternal plasma leptin concentrations. Preeclampsia is frequently related to generation of small for gestational age (SGA) infant especially in cases with severe preeclampsia. However, it is still controversial whether the increase in maternal plasma leptin levels is associated with fetal growth restriction without complication of preeclampsia. Therefore, the aim of the present study was to explore the relationship between maternal plasma leptin levels and fetal growth in non-preeclamptic (n = 98) and preeclamptic (n = 40) women. In non-preeclamptic pregnant women, plasma leptin levels in SGA group (n = 11) were significantly higher than those in appropriate for gestational age (AGA) group (n = 87, P < 0.05). In pregnant women with preeclampsia, likewise, plasma leptin levels in SGA group (n = 15) were significantly higher than those in AGA group (n = 25, P < 0.05). In multiple linear regression analysis, maternal BMI, mean arterial blood pressure and DeltaSD of neonatal body weight were significant factors for determining maternal plasma leptin levels in all population studied. Maternal BMI and DeltaSD of neonatal body weight showed positive correlation with maternal plasma leptin levels when analysis was performed in non-preeclamptic subjects alone. In conclusion, maternal plasma leptin levels reflect, at least partly, deterioration in fetal growth. [Abstract/Link to Full Text]

Kanazawa Y, Igarashi Y, Komiya K, Sakurai Y, Shimizu T, Fujitani Y, Tanaka Y, Watada H, Kawamori R, Hirose T
Long-Term Efficacy of Insulin Glargine After Switching from NPH Insulin as Intensive Replacement of Basal Insulin in Japanese Diabetes Mellitus. Comparison of Efficacy between Type 1 and Type 2 Diabetes (JUN-LAN Study 1).
Endocr J. 2007 Nov 14;
To assess and compare the efficacy and safety of insulin glargine as intensive replacement of basal insulin in Japanese patients with type 1 (n=72) and type 2 (n=46) diabetes, we switched their intensive insulin regimen from NPH plus regular or rapid-acting insulin to glargine plus bolus insulin, which included regular and rapid-acting insulin, and recorded changes in glycemic control and frequency of hypoglycemia for 18 months. The dose titration of basal and bolus insulin was based on home self-monitored blood glucose measurements and monthly HbA(1C). Mean HbA(1C) level was improved significantly at 3 months after switching to glargine plus bolus insulin regimen and this effects continued for 18 months in both type 1 and type 2 diabetes patients (HbA(1C) level: type 1: baseline 8.9+/-2.6%, 18 months 7.8+/-1.5% (p<0.05), type 2: baseline 8.2+/-2.6%, 18 months 7.7 +/-1.5%. Body weight was slightly but significantly increased at 18 months only in type 2 diabetes. Total daily bolus insulin doses were not changed but basal insulin could be increased significantly after switching regimens in both types diabetes compared with baseline. The frequency of mild to moderate hypoglycemia (self-assisted episodes, blood glucose <70 mg/dl) was marginally lower with glargine but not significantly. Self-monitored fasting blood glucose level was significantly improved after switching in type 2 diabetes. Patients with the worst HbA(1C) level at baseline exhibited more than 10% improvement in HbA(1C) level after switching both type 1 and type 2 diabetes. The HbA(1C) levels of the effectively treated patients were comparable to those of ineffectively treated ones at 6 months and the same improvement was seen at 18 months. Our results suggested that insulin glargine is more effective than NPH insulin as intensive replacement of basal insulin, particularly in those Japanese patients with difficult glycemic control with NPH insulin, equally in both type 1 and type 2 diabetes. [Abstract/Link to Full Text]

Kashimada KI, Onishi T, Ono M, Miyai K, Ohta M, Mizutani S
A Boy with "Transient" Growth Hormone Deficiency in Prepubertal Stage Despite Normal Growth Hormone Secretion in Childhood and after Puberty.
Endocr J. 2007 Nov 14;
Transient growth hormone deficiency (GHD) is occasionally found in prepubertal individuals, and this phenomenon has been variously interpreted. Sex steroids enhance GH secretion; however, the cut-off values of provocative GH tests are not modified according to the physiological changes. Physiological changes in sex steroid levels are thought to cause the image of transient GHD. In addition, the reproducibility of provocative GH tests makes the interpretation complicated. We experienced a case of a boy with short stature who had undergone provocative GH tests at three different times: childhood (5 and 7 years old), before puberty (12 years old), and in adolescence (15 years old). Although the responses of GH in his childhood and adolescence were within the normal range, his prepubertal GH response was extremely low, as if he had "complete" GHD (peak GH: insulin test, 0.60 ng/ml; clonidine test, 0.78 ng/ml). No morphological changes were observed in the pituitary gland or hypothalamus on MRI. The level of insulin-like growth factor 1 was in the normal range for his age at this time. Here, we report the clinical course and endocrinological data of this case, and suggest that transient GHD is caused not only by the physiological effects of sex steroids but also by certain mechanisms that actively reduce GH secretion. [Abstract/Link to Full Text]

Fukui M, Soh J, Tanaka M, Kitagawa Y, Hasegawa G, Yoshikawa T, Miki T, Nakamura N
Low Serum Testosterone Concentration in Middle-aged Men with Type 2 Diabetes.
Endocr J. 2007 Nov 12;
Low concentrations of endogenous androgens have been linked with insulin resistance and atherosclerosis. Men with diabetes have been reported to have lower serum testosterone concentration than non-diabetic men; however, there has never been a large study. The aim of this study was to investigate if endogenous androgen concentration is certainly lower in a relatively large number of Japanese patients with type 2 diabetes compared with healthy men, and to identify what factors may be associated with low serum testosterone concentrations in men with type 2 diabetes. Serum free testosterone concentrations were measured in 524 healthy men and in 331 consecutive Japanese men with type 2 diabetes between 40 and 69 years old. In addition, we investigated the relationships between serum free testosterone concentration and luteinizing hormone (LH) concentration as well as major cardiovascular risk factors including age, blood pressure, plasma lipid concentration, glycemic control (HbA(1c)), and BMI. Serum free testosterone concentrations were lower in men with type 2 diabetes than in healthy men in the 40-49 years group (10.9 +/- 3.3 vs. 14.0 +/- 3.6 pg/ml, P<0.0001), in the 50-59 years group (10.4 +/- 3.2 vs. 12.1 +/- 2.9 pg/ml, P<0.0001), and in the 60-69 years group (9.5 +/- 2.6 vs. 10.5 +/- 2.9 pg/ml, P = 0.0104). A negative correlation was found between serum free testosterone and LH concentrations (r = -0.326, P<0.0001). In conclusion, serum free testosterone concentration is certainly lower in a relatively large number of Japanese patients with type 2 diabetes compared with healthy men with each decade of life between 40 and 69 years old. [Abstract/Link to Full Text]

Santoh T, Watanabe M, Kuroda S, Ueda D, Iwatani Y
Ratio of Serum IgG(3) to Total IgG Concentration and Goiter Size Are Independent Factors in Intractability of Graves' Disease.
Endocr J. 2007 Nov 12;
Peripheral immunoglobulin (Ig) G(3)-secreting cells and serum concentrations of interleukin (IL)-10, a class-switching factor to IgG(3)-secreting cells, increase in patients with intractable Graves' disease (GD). However, they are not practical for laboratory tests. To find more stable and easily detectable markers of disease intractability or disease severity in patients with GD or Hashimoto's disease (HD), we examined the serum concentration of IgG(3) in 58 euthyroid GD patients who had been undergoing antithyroid drug treatment for more than 5 years but still must continue drug treatment to maintain a euthyroid state (intractable GD), 26 GD patients who had maintained a euthyroid state for more than 2 years without any treatment (GD in remission), 20 untreated, thyrotoxic GD patients, 40 euthyroid HD patients treated with thyroxine (5 men and 35 women), 13 untreated, euthyroid HD patients, and 39 healthy volunteers. Serum concentrations of IgG(3 )increased in euthyroid patients with intractable GD and in those with GD in remission, but serum concentrations of IgG were not altered. The ratio of serum concentrations of IgG(3) to total IgG (IgG(3)/IgG ratio) was higher in euthyroid patients with intractable GD than in those with GD in remission. Multiple logistic-regression analysis demonstrated that IgG(3)/IgG ratio and goiter size were independent factors in disease intractability of GD patients. These results suggest that IgG(3)/IgG ratio and goiter size may be used as independent markers associated with GD intractability. [Abstract/Link to Full Text]

Ohwada R, Hotta M, Sato K, Shibasaki T, Takano K
The Relationship between Serum Levels of Estradiol and Osteoprotegerin in Patients with Anorexia Nervosa.
Endocr J. 2007 Nov 12;
Osteoporosis is one of the major complications in anorexia nervosa (AN) patients. Receptor activator of nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) have been identified as important regulators of bone turnover. The objective of this study was to clarify the role of RANK-RANKL-OPG system, and their relationship with other regulators for bone metabolism in AN patients. We investigated serum levels of RANKL, OPG, and bone turnover markers of 26 Japanese young female AN patients and 7 age-matched healthy women. We measured serum levels of estradiol (E2), insulin like growth factor-I (IGF-I) and triiodothyronin (T3) from the same samples and studied their relationship with RANKL or OPG. Mean serum levels of E2, IGF-I, T3 and leptin in AN patients were significantly lower than those of controls (p<0.05). Serum levels of OPG in AN patients were significantly higher than those in controls and negatively correlated with body mass index (BMI), E2, IGF-I or leptin. Serum levels of free RANKL could not be detected except for only one healthy control in both groups. These results suggest that serum OPG levels may be increased by a compensatory mechanism for malnutrition and estrogen deficiency which induces an increase in bone resorption. [Abstract/Link to Full Text]

Isguven P, Arslanoglu I, Erol M, Yildiz M, Adal E, Erguven M
Serum Levels of Ghrelin, Leptin, IGF-I, IGFBP-3, Insulin, Thyroid Hormones and Cortisol in Prepubertal Children with Iron Deficiency.
Endocr J. 2007 Nov 12;
The aim of the present study is to investigate possible alterations in ghrelin and other hormone levels related to appetite and somatic growth in children with iron deficiency anemia. Twenty-five patients and 25 healthy controls that were prepubertal and within normal limits regarding height and BMI standard deviation scores were recruited. Ghrelin, leptin, IGF-I, IGFBP-3, insulin, thyroid hormones and cortisol levels were studied. Ghrelin, insulin and IGF-I levels were significantly low in the study group (ghrelin 13.58 +/- 16.32 vs. 35.39 +/- 23.69 ng/ml, p<.001; insulin 3.41 +/- 2.42 vs. 5.67 +/- 1.09 mU/ml, p=.008 and IGF-I 126.94 +/- 92.82 vs. 203 +/- 105.1 ng/ml, p=.015). We concluded that low ghrelin and insulin levels might be causes of the appetite loss in iron deficiency and as a result of appetite loss and undernutrition as well as by direct effects they might be related with growth retardation, which could be also influenced by low IGF-I levels. [Abstract/Link to Full Text]

Adachi M, Asakura Y, Sato Y, Tajima T, Nakajima T, Yamamoto T, Fujieda K
Novel SLC12A1 (NKCC2) Mutations in Two Families with Bartter Syndrome Type 1.
Endocr J. 2007 Nov 12;
Bartter syndrome (BS) type 1, also referred to antenatal BS, is a genetic tubulopathy with hypokalemic metabolic alkalosis and prenatal onset of polyuria leading to polyhydramnios. It has been shown that BS type 1 is caused by mutations in the SLC12A1 gene encoding bumetanide-sensitive Na-K-2Cl(-) cotransporter (NKCC2). We had the opportunity to care for two unrelated Japanese patients of BS type 1 with typical manifestations including polyhydramnios, prematurity, hypokalemia, alkalosis, and infantile-onset nephrocalcinosis. Analysis of the SLC12A1 gene demonstrated four novel mutations: N117X, G257S, D792fs and N984fs. N117X mutation is expected to abolish most of the NKCC2 protein, whereas G257, which is evolutionary conserved, resides in the third transmemebrane domain. The latter two frameshift mutations reside in the intra-cytoplasmic C-terminal domain, which illustrates the importance of this domain for the NKCC2 function. In conclusion, we found four novel SLC12A1 mutations in two BS type 1 patients. Development of effective therapy for hypercalciuria is mandatory to prevent nephrocalcinosis and resultant renal failure. [Abstract/Link to Full Text]

Huang H, Tada Iida K, Murakami H, Saito Y, Otsuki T, Iemitsu M, Maeda S, Sone H, Kuno S, Ajisaka R
Influence of Adiponectin Gene Polymorphism SNP276 (G/T) on Adiponectin in Response to Exercise Training.
Endocr J. 2007 Nov 2;
Adiponectin is an adipocytokine that is involved in insulin sensitivity. The adiponectin gene contains a single nucleotide polymorphism (SNP) at position 276 (G/T). The GG genotype of SNP276 (G/T) is associated with lower plasma adiponectin levels and a higher insulin resistance index. Therefore, we examined the influence of SNP276 (G/T) on the plasma level of adiponectin in response to exercise training. Thirty healthy Japanese (M12/F18; 56 to 79 years old) performed both resistance and endurance training, 5 times a week for 6 months. The work rate per kg of weight at double-product break-point (DPBP) was measured. Blood samples were obtained before and after the experiment. Plasma concentrations of adiponectin, HbA1c, insulin, glucose, total, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) cholesterol, and triglyceride were measured. Genotypes of SNP276 were specified. Student's t-test for paired values and unpaired values was used. After the 6-month training period, the work rate per kg of weight at DPBP and the plasma HDL-cholesterol level were significantly improved (P<0.05), while no change was observed in the total plasma adiponectin level. However, the plasma adiponectin level in those with the GT+TT genotype had significantly increased (P<0.05). Additionally, the degree of the decrease in the HOMA-R level was significantly greater in the subjects with the GT+TT genotype than those with the GG genotype (p<0.05). Our results suggest that subjects with the genotype GT+TT at SNP276 (G/T) have a greater adiponectin-related response to exercise training than those with the GG genotype. [Abstract/Link to Full Text]

Kodera R, Otsuka F, Inagaki K, Miyoshi T, Ogura T, Tanimoto Y, Sei T, Makino H
Case Report: Gastric Diverticulum Simulating Left Adrenal Incidentaloma in a Hypertensive Patient.
Endocr J. 2007 Nov 2;
A 46-year-old Japanese male with hypertension was referred for examination of left adrenal tumor incidentally detected by computed tomography (CT) scan. The patient had a 4-month history of hypertension. Abdominal CT demonstrated a low-density mass 2.5 cm in diameter in the left adrenal region that was observed as a high-intense lesion with T2-weighted magnetic resonance imaging. (131)I-adosterol scintigraphy showed normal uptake of bilateral adrenals. The adrenocortical hormone levels were within normal ranges; however, urinary noradrenaline excretion was slightly elevated, likely due to concurrent sleep apnea syndrome. Based on the observation of a very tiny bubble in the ventral portion of the adrenal mass by careful review of CT images examined at a previous hospital, a restudy of abdominal CT with oral contrast was performed. In this restudy abdominal CT we observed positive enhancement of the left adrenal mass, indicating that the adrenal mass was a diverticulum derived from posterior gastric fornix. The present case study reinforces that preoperative differentiation from mimic adrenal tumors is necessary in cases of cystic adrenal mass in the left adrenal region. [Abstract/Link to Full Text]

Oda E
Is Central Obesity a Good Predictor of Carotid Atherosclerosis in Japanese Type 2 Diabetes with Metabolic Syndrome? Comment on the Article by Yasuda et al.
Endocr J. 2007 Nov 2; [Abstract/Link to Full Text]

Oda E
High-Sensitivity C-Reactive Protein (CRP) May Be Superior to Anthropometric Parameters as a Marker of Metabolic Consequences Due to Obesity. Comment on the Article by Komatsu et al.
Endocr J. 2007 Nov 2; [Abstract/Link to Full Text]

Chanda D, Park JH, Choi HS
Molecular Basis of Endocrine Regulation by Orphan Nuclear Receptor Small Heterodimer Partner.
Endocr J. 2007 Nov 2;
Nuclear receptors (NRs) are a unique superfamily of transcription factors (TFs) which are involved in and play a crucial role in almost all aspects of mammalian physiology. Small Heterodimer Partner (SHP; NR0B2), an exceptional member of this superfamily of NRs, have been identified as a key regulatory factor of the transcription of a variety of genes involved in diverse metabolic pathways, and are thereby an important factor in a variety of physiological functions. Since its discovery a decade ago, considerable progress has been made in the elucidation of the underlying mechanism by which SHP regulates various metabolic processes, and the results of previous studies support its importance in the maintenance of metabolic homeostasis. In this review, we have evaluated the current state of understanding of the molecular mechanisms and the resultant physiological interpretations governed by SHP. [Abstract/Link to Full Text]

Kumagai A, Reiners C, Drozd V, Yamashita S
Childhood Thyroid Cancers and Radioactive Iodine Therapy: Necessity of Precautious Radiation Health Risk Management.
Endocr J. 2007 Oct 15;
One of the lessons from Chernobyl's legacy on health impact beyond 20 years is not only how to detect and treat the patients with radiation-associated thyroid cancers but how to follow up those who received radioactive iodine treatment repetitively after surgery in order to monitor any recurrence/worsening and also how to predict the risk of secondary primary cancers for their lifetime period. To evaluate the possibility of second primary tumors after radioactive iodine treatment, we reviewed the reports on risks from both external and internal radiation exposure, especially at high doses during childhood through an internet service of the National Library of Medicine and the National Institutes of Health, PubMed by the end of June, 2007, together with our own experience of Chernobyl childhood thyroid cancers. Children who were internally exposed after Chernobyl accident have a long-term risk of well differentiated thyroid cancers. Once they have disease, ironically radioactive iodine ablation is one of the useful therapies after surgical treatment. Elevated risks of solid cancers and leukemia have been found in radioiodine-treated patients, however, so far precious few reports from Chernobyl thyroid cancer patient were published. To reduce the adverse effects of radioactive iodine therapy on non-target tissues, recombinant human TSH has been applied and proved effective. Period of latency of second primary cancers may be very long. Therefore patients treated with high activities of radioactive iodine, especially children cases, should be carefully followed up during their whole lifespan. [Abstract/Link to Full Text]

Aoki F, Kojima I
Therapeutic Potential of Follistatin to Promote Tissue Regeneration and Prevent Tissue Fibrosis.
Endocr J. 2007 Oct 15; [Abstract/Link to Full Text]

Kaneto H, Miyatsuka T, Kawamori D, Yamamoto K, Kato K, Shiraiwa T, Katakami N, Yamasaki Y, Matsuhisa M, Matsuoka TA
PDX-1 and MafA Play a Crucial Role in Pancreatic beta-Cell Differentiation and Maintenance of Mature beta-Cell Function.
Endocr J. 2007 Oct 15;
Pancreatic and duodenal homeobox factor-1 (PDX-1) plays a crucial role in pancreas development, beta-cell differentiation, and maintenance of mature beta-cell function. PDX-1 expression is maintained in pancreatic precursor cells during pancreas development but becomes restricted to beta-cells in mature pancreas. In mature beta-cells, PDX-1 transactivates the insulin and other genes involved in glucose sensing and metabolism such as GLUT2 and glucokinase. MafA is a recently isolated beta-cell-specific transcription factor which functions as a potent activator of insulin gene transcription. Furthermore, these transcription factors play an important role in induction of insulin-producing cells in various non-beta-cells and thus could be therapeutic targets for diabetes. On the other hand, under diabetic conditions, expression and/or activities of PDX-1 and MafA in beta-cells are reduced, which leads to suppression of insulin biosynthesis and secretion. It is likely that alteration of such transcription factors explains, at least in part, the molecular mechanism for beta-cell glucose toxicity found in diabetes. [Abstract/Link to Full Text]

Tateno T, Izumiyama H, Doi M, Akashi T, Ohno K, Hirata Y
Defective Expression of Prohormone Convertase 1/3 in Silent Corticotroph Adenoma.
Endocr J. 2007 Oct 2;
Silent corticotroph adenoma (SCA) is defined as an ACTH-producing pituitary tumor not associated with clinical and endocrine feartures of Cushing's syndrome, but its underlying molecular mechanism(s) remains unknown thus far. We tested the hypothesis that reduced expression of prohormone convertase (PC) 1/3 responsible for proteolytic processing of proopiomelanocortin (POMC) in SCA may lead to production of unprocessed, biologically inactive POMC and/or precursor of ACTH. Among 30 non-functioning pituitary macroadenomas (NFA) examined, we found 6 SCAs by immunohistochemical study using anti-ACTH antibody. Preoperative endocrine and diagnostic image tests did not reveal any differences between SCA and the remaining NFA except for the higher recurrence rate of SCA. While steady-state PC1/3 mRNA levels determined by RT-PCR were almost comparable between SCAs and NFAs, immunohistochemical study showed negative immunostaining for PC1/3 in all 6 SCAs. Our data suggest that defective PC1/3 expression may lead to preferential production of unprocessed, biologically inactive ACTH variants in SCA. [Abstract/Link to Full Text]

Tagami T, Usui T, Shimatsu A, Naruse M
Toxic Thyroid Adenoma Presenting as Hypokalemic Periodic Paralysis.
Endocr J. 2007 Oct 2;
Toxic thyroid adenoma presenting as hypokalemic periodic paralysis is extraordinarily rare. We describe a 26-year-old Japanese man who suffered from acute and painful muscle weakness of extremity in the morning. Physical examination showed a left anterior neck mass and laboratory tests revealed hypokalemia during his paralysis, and thyrotoxicosis. Neck sonogram showed a solitary nodule in the left lobe of the thyroid. Thyroid scintigraphy revealed a hot nodule of the tumor region with suppressed uptake in the other thyroid area. The tumor was surgically removed and his paralytic attack ceased. No somatic mutation of TSH receptor was found in his thyroid adenoma and no known genetic mutations of ionic channel genes, such as calcium (CACN1S), sodium (SCN4A) and potassium (KCNE3), were found. Although thyrotoxic periodic paralysis is usually accompanied with Graves' disease, thyrotoxicosis of other conditions including Plummer's disease should be considered. [Abstract/Link to Full Text]

Majima T, Komatsu Y, Shimatsu A, Satoh N, Fukao A, Ninomiya K, Matsumura T, Nakao K
Clinical Significance of 1-year treatment with Raloxifene on Bone and Lipid Metabolism in Japanese Postmenopausal Women with Osteoporosis.
Endocr J. 2007 Oct 2;
It has been well established that raloxifene (RLX) has beneficial effects on bone primarily in Caucasian women. However, to date, there is a dearth of data for Japanese postmenopausal women. In this study, we prospectively evaluated the effects of RLX on bone and lipid metabolism in fifty Japanese postmenopausal patients with untreated osteoporosis. We measured bone mineral density (BMD) by dual-energy X-ray absorptiometry at 7 sites including the lumbar spine, femoral neck, and distal radius. BMD was significantly increased at the lumbar spine both at 6 months and at 12 months compared with at baseline (p<0.01 for both), although the possibility could not be completely excluded that this increase may be partly explained by an apparent increase induced by degenerative changes in lumbar vertebrae since we had no control subjects to compare and be more certain of the findings in this study. Both bone-specific alkaline phosphatase (BAP) and serum N-terminal telopeptide of type I collagen (NTx) significantly decreased both at 6 months (p<0.01 for both) and at 12 months (p<0.01 for both) compared with at baseline, but not below the lower limit of the reference value. Total cholesterol and low-density lipoprotein cholesterol were significantly improved while triglycerides and high-density lipoprotein cholesterol were unaltered. Although longer and larger studies with fracture endpoints are needed to draw definite conclusions, our findings suggest the favorable effects of RLX on bone and lipid metabolism in Japanese postmenopausal women with osteoporosis as in Caucasian women. [Abstract/Link to Full Text]

Miyata I, Abe-Gotyo N, Tajima A, Yoshikawa H, Teramoto S, Seo M, Kanno KI, Sugiura K, Tanaka T, Eto Y
Successful Intrauterine Therapy for Fetal Goitrous Hypothyroidism during Late Gestation.
Endocr J. 2007 Oct 3;
We experienced a case of fetal goitrous hypothyroidism in an infant delivered by a 33-year-old woman receiving 300 mg/day of propylthiouracil (PTU) for hyperthyroidism due to Graves' disease. A large fetal goiter (maximum diameter, 60 mm) was detected by magnetic resonance imaging (MRI) at 36 weeks of gestation. Initial fetal blood sampling revealed hypothyroidism with a serum thyroid-stimulating hormone (TSH) of 99 muIU/mL, free triiodothyronine (T3) of 1.97 pg/mL, and free thyroxine (T4) of 0.29 ng/dL. Consequently, a diagnosis of fetal goitrous hypothyroidism due to transplacental passage of maternal PTU was made. To reduce the risk of perinatal complications, 300 mug of levothyroxine sodium (L-T4) was administered into the maternal amniotic fluid twice between 37 and 38 weeks of gestation. Subsequent fetal MRI showed that the size of goiter had decreased. At 38 weeks and 5 days of gestation, a 3042-g male infant was born by cesarean section. There were no severe complications at delivery, although mild tachypnea was observed and the infant's thyroid gland was slightly enlarged. He was treated with L-T4 for two weeks. At present, his growth and neurological development are normal. This case indicates that intrauterine therapy by the intraamniotic administration of L-T4 can be effective in treating fetal goitrous hypothyroidism even during late gestation. [Abstract/Link to Full Text]

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Recent Articles in Minerva Endocrinologica

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Rizzo M, Rini GB, Carmina E
Androgen excess and cardiovascular risk.
Minerva Endocrinol. 2007 Mar;32(1):67-71.
Cardiovascular diseases represent the major cause of death in most of developed countries and ultimately kill as many men as women. Both genders are exposed to the same risk factors but their rates of cardiovascular morbidity and mortality are very different until old age. This represents a crucial point; in fact, only at age 75 and over cardiovascular rates of women approximate those of men. It has been suggested that differences in hormonal status and mainly in androgen levels may explain such gender disparity. Consistently with this hypothesis, it has been shown that women with polycystic ovary syndrome (PCOS) have elevated cardiovascular risk despite their young age. However, the possibility that androgens may increase cardiovascular risk remains controversial. Hyperandrogenism, as isolated androgen excess, has not been clearly recognised so far as a risk factor for cardiovascular diseases. In addition, the risk of premature cardiovascular diseases in PCOS is at present uncertain. Long-term studies examining the prevalence of cardiovascular diseases among women with PCOS did not demonstrate a clear increased risk for cardiovascular morbidity and mortality. Thus, it seems that androgens have a limited role in inducing cardiovascular risk; the altered risk factors found in women with PCOS are mainly dependent on the metabolic components of this syndrome as well as on insulin resistance and reduced adiponectin secretion. [Abstract/Link to Full Text]

Davis JD, Tremont G
Neuropsychiatric aspects of hypothyroidism and treatment reversibility. .
Minerva Endocrinol. 2007 Mar;32(1):49-65.
Thyroid hormone has important actions in the adult brain, and it is well accepted that hypothyroidism is associated with neuropsychiatric complaints and symptoms. Neuropsychiatric symptoms refer to a spectrum of emotional and cognitive problems that are directly related to changes in the brain secondary to multiple factors, including the direct effects of thyroid disease, as well as hormone deprivation in brain tissue. Hypothyroidism impacts aspects of cognitive functioning and mood. More severe hypothyroidism can mimic melancholic de-pression and dementia. Neuropsychiatric symptoms tend to improve with treatment and normalization to a euthyroid state, though the pattern is inconsistent and complete recovery is uncertain. The degree to which mild hypothyroidism, or subclinical hypothyroidism (SCH), impacts mood and cognitive functions and whether these symptoms respond to treatment, remains controversial. Most studies support a relationship between thyroid state and cognition, particularly slowed information processing speed, reduced efficiency in executive functions, and poor learning. Furthermore, hypo-thyroidism is associated with an increased susceptibility to depression and reductions in health-related quality of life. Controlled studies suggest that cognitive and mood symptoms improve with treatment, though the data are equivocal and limited by diverse methodologies. Functional neuroimaging data provide support for the mood and cognitive findings and treatment reversibility for both overt and SCH. These findings are not, however, without controversy. Recent investigations into the impact of SCH on cognition and mood, coupled epidemiological studies investigating the normal spectrum of thyroid stimulating hormone, have fueled significant debate regarding the appropriate, healthy range for TSH levels. This has led to concern over whether patients with overt hypothyroidism may be undertreated and whether SCH patients are truly out of the range of normal thyroid functioning and should be treated. The following is a review of the extant literature on the impact of hypothyroidism on cognition and mood, reversibility of symptoms, and treatment approaches. The spectrum of thyroid disease is reviewed, but mild, or subclinical, hypothyroidism is emphasized. The potential role of autoimmunity in neuropsychiatric symptoms and treatment resistance is addressed. Limitations of the current literature and future directions are discussed. [Abstract/Link to Full Text]

Diamanti-Kandarakis E, Christakou C, Kandarakis H
Polycystic ovarian syndrome: the commonest cause of hyperandrogenemia in women as a risk factor for metabolic syndrome.
Minerva Endocrinol. 2007 Mar;32(1):35-47.
Polycystic ovarian syndrome (PCOS), the commonest endocrine disorder of women, is currently emerging as a potential facet of the metabolic syndrome (MBS) in women. Available data suggest that the MBS or, alternatively, individual metabolic risk factors may be overly present and most importantly that MBS may arise at a significantly younger age among PCOS women. The concept that a conventionally considered reproductive disorder may entail a significant metabolic impact on affected women has warranted medical interest on the mechanisms underlying the multiplicative sequelae of PCOS. Although obesity indisputably compounds the clinical course of women with PCOS, this appears to be just the tip of the iceberg. Insulin resistance and hyperinsulinemia have been intuitively involved as a critical link due to their contribution to the pathophysiology and clinical presentation of both PCOS and MBS. Hyperandrogenemia, the predominant endocrine hallmark of PCOS, has also been implicated as a contributing factor to the suggested interrelationship. [Abstract/Link to Full Text]

Blumenfeld Z
Gender difference: fertility preservation in young women but not in men exposed to gonadotoxic chemotherapy.
Minerva Endocrinol. 2007 Mar;32(1):23-34.
Decreased secretion of pituitary gonadotropins, by decreasing gonadal function, may possibly protect against the sterilizing effects of chemotherapy. Although previous claims that primordial germ cells fare better than germ cells that are part of an active cell cycle have been made, this hypothesis has not been seriously tested clinically until recently. The only prospective randomized study performed to date found that gonadotropin releasing hormone agonistic analogue (GnRH-a) protected the ovary against cyclophosphamide-induced damage in Rhesus monkeys by significantly decreasing the number of follicles lost during the chemotherapeutic insult. We have administered a monthly depot i.m. injection of GnRH-a to more than 125 young patients exposed to gonadotoxic chemotherapy for malignant or nonmalignant diseases, after informed consent, starting before chemotherapy for up to 6 months, in parallel and until the end of chemotherapeutic treatment. Less than 7% developed irreversible hypergonadotropic amenorrhea. The remainder (>93%) resumed cyclic ovarian function, of which 32 patients spontaneously conceived 46 times. These patients were compared to a control group of over 125 patients of comparable age (15-40 years), who were similarly treated with chemotherapy but without the GnRH-a adjuvant. The 2 groups were similar in age, diagnosis, and the ratio of HD to non-Hodgkin lymphoma patients. The 2 groups also received similar doses of radiotherapy exposure and the proportion of radio-plus chemotherapy-treated patients was similar. The cumulative doses of each chemotherapeutic agent and the mean or median radiotherapy exposure did not differ between the groups. Our and others' results support the effectiveness of GnRH-a administration also to patients receiving cyclophosphamide pulses for systemic lupus erythematosus and other autoimmune diseases. Possible explanations for the beneficial effect of the GnRH-a on minimizing the gonadotoxic effect of chemotherapy are discussed. Multi-center prospective, randomized studies are awaited to substantiate the in vivo effect of GnRH-a as an unequivocal means of minimizing follicular apoptosis. [Abstract/Link to Full Text]

Tomlinson JW
11Beta-hydroxysteroid dehydrogenase type 1 in human disease: a novel therapeutic target.
Minerva Endocrinol. 2005 Mar;30(1):37-46.
Patients with cortisol excess, Cushing's syndrome, develop a classical phenotype characterized by central obesity, hypertension, and increased cardiovascular mortality. Whilst this observation points to the importance of glucocorticoids, circulating cortisol excess is rare and does not explain the pathogenesis of many common conditions. At a tissue specific level, the enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) locally regenerates active cortisol from inactive cortisone amplifying glucocorticoid receptor activation in the context of normal circulating cortisol levels. Increased 11beta-HSD1 activity and expression have been implicated in the pathogenesis of many common conditions including, obesity, insulin resistance, the metabolic syndrome, polycystic ovarian syndrome, osteoporosis and glaucoma. Furthermore, selective 11beta-HSD1 inhibition has been proposed as a novel therapeutic strategy in many of these conditions. Here we review the role of 11beta-HSD1 in human disease and discuss the impact of selective 11beta-HSD1 inhibition. [Abstract/Link to Full Text]

Prelevic GM, Kocjan T, Markou A
Hormone replacement therapy in postmenopausal women.
Minerva Endocrinol. 2005 Mar;30(1):27-36.
From the endocrine point of view, menopause is considered a deficiency state and menopausal hormone replacement therapy (HRT) regarded as restoring the premenopausal endocrine milieu. Millions of healthy postmenopausal women were taking HRT in late 1990's many in the absence of menopausal symptoms. The major benefit from HRT was considered to be cardiovascular protection and also protection against osteoporosis and Alzheimer's Disease. The Women's Health Initiative (WHI) trial and other studies published since 2002 fundamentally changed our understanding of risks and benefits associated with HRT. This review discusses the effects of HRT on menopausal symptoms, cognitive function, cardiovascular disease, osteoporosis and also breast and bowel cancer. [Abstract/Link to Full Text]

Lindberg MK, Vandenput L, Movèrare Skrtic S, Vanderschueren D, Boonen S, Bouillon R, Ohlsson C
Androgens and the skeleton.
Minerva Endocrinol. 2005 Mar;30(1):15-25.
Loss of estrogens or androgens causes bone loss by increasing the rate of bone remodeling, and also causes an imbalance between resorption and formation by prolonging the lifespan of osteoclasts and shortening the lifespan of osteoblasts. Conversely, treatment with androgens, as well as estrogens, maintains cancellous bone mass and integrity, regardless of age or sex. Both androgens, via the androgen receptor (AR), and estrogens, via the estrogen receptors (ERs) can exert these effects, but the relative contribution of these 2 pathways remains uncertain. Androgens, like estrogens, stimulate endochondral bone formation at the start of puberty, whereas they induce epiphyseal closure at the end of puberty, thus, they have a biphasic effect. Androgen action on the growth plate is, however, clearly mediated via aromatization into estrogens and interaction with ER alpha. Androgens increase, while estrogens decrease radial growth. This differential effect of the sex steroids may be important because bone strength in males seems to be determined by higher periosteal bone formation and, therefore, greater bone dimensions. Experiments in mice suggest that both the AR and ER alpha pathways are involved in androgen action on radial bone growth. ER beta may mediate growth-limiting effects of estrogens in the female but does not seem to be involved in the regulation of bone size in males. In conclusion, androgens may protect men against osteoporosis via maintenance of cancellous bone mass and expansion of cortical bone. This androgen action on bone is mediated by the AR and ER alpha. [Abstract/Link to Full Text]

Svensson J, Tivesten A, Isgaard J
Growth hormone and the cardiovascular function.
Minerva Endocrinol. 2005 Mar;30(1):1-13.
In this review, the great importance of growth hormone (GH) for the maintenance of cardiac function in adult life is discussed. Physiological effects of GH are discussed as well as the cardiac dysfunction caused both by GH excess (acromegaly) and by GH deficiency in adult hypopituitary patients. In both acromegaly and adult GH deficiency, there is also increased cardiovascular morbidity and mortality. Finally, the effect of GH treatment in heart failure is discussed. [Abstract/Link to Full Text]

Chanson P, Salenave S
Diagnosis and treatment of pituitary adenomas.
Minerva Endocrinol. 2004 Dec;29(4):241-75.
Pituitary tumors cause symptoms by secreting hormones (prolactin, PRL, responsible for amenorrhea-galactorrhea in women and decreased libido in men; growth hormone, GH, responsible for acromegaly; adrenocorticotropic hormone, ACTH, responsible for Cushing's syndrome; thyroid-stimulating hormone, TSH, responsible for hyperthyroidism), depressing the secretion of hormones (hypopituitarism), or by mass-related effects (headaches, visual field abnormalities...). All patients with pituitary tumors should be evaluated for gonadal, thyroid and adrenal function as well as PRL and GH secretion. Specific stimulation and suppression tests for pituitary hormones are performed in selected situations for detecting the type of hypersecretion or the response to treatment. Imaging procedures (mainly magnetic resonance imaging, MRI, nowadays) determine the presence, size and extent of the lesion. The classification of pituitary tumors is based on the staining properties of the cell cytoplasm viewed by light microscopy and immunocytochemistry revealing the secretory pattern of the adenoma. Treatment of pituitary adenomas consists of surgery (performed in more than 99% of cases via a transphenoidal route) and radiotherapy, generally fractionated or, in selected cases, using stereotactic techniques such as gamma-knife. The availability of medical treatment (dopamine, DA, agonists, somatostatin analogs, GH-receptor antagonists...) has profoundly modified the indications of radiotherapy, drugs being now generally used as a second-line treatment, after surgery (or even as first-line treatment). Based on the results of the different treatment modalities for each type of pituitary adenoma, recommendations will be proposed. They may be summarized as follows. For treatment of GH-secreting adenomas, trans-sphenoidal surgery is the first-line therapy except when the macroadenoma is giant or if surgery is contra-indicated; postoperative radiation therapy (fractionated, or by gamma-knife) is performed for partially resected tumors or when GH levels remain elevated (eventually after a trial of somatostatin analog). Somatostatin analogs, now available in slow release form, are proposed when surgery is contra-indicated, or has failed to normalize GH levels, or in waiting for the delayed effects of radiation therapy. If the probability of surgical cure is low (e.g. in patients with very large and/or invasive tumors), then somatostatin analogs may be reasonable primary therapeutic modality provided that the tumor does not threaten vision or neurological function. Pegvisomant, the new GH-receptor antagonist, is indicated in case of resistance to somatostatin analogs. Patients with PRL-secreting microadenomas may be treated either with trans-sphenoidal surgery or medically with DA agonists. In patients with macroadenomas, even in the presence of chiasmatic syndrome, DA agonists are now proposed as primary treatment. Indeed, effects on visual disturbances are often very rapid (within a few hours or days) and tumoral shrinkage is usually very significant. For patients with ACTH-secreting adenomas, primary therapy is generally trans-sphenoidal surgery by a skilled surgeon, whether or not a microadenoma is visible on MRI. Radiotherapy is reserved for patients who are subtotally resected or remain hyper-secretory after surgery. In waiting for the effects of radiotherapy, adrenal steroidogenesis inhibitors (mitotane, ketoconazole) may be indicated. If drugs are not available or not tolerated, bilateral adrenalectomy may be proposed. For patients with clinically non functioning adenomas (generally gonadotropin-secreting adenomas on immunocytochemistry), trans-sphenoidal surgery with or without postoperative radiation therapy is performed for almost all patients whether or not they have visual consequences of their tumor. Selected patients with small, incidentally discovered microadenomas may be carefully followed without immediate therapy. [Abstract/Link to Full Text]

Arosio M, Ronchi CL, Epaminonda P, di Lembo S, Adda G
New therapeutic options for acromegaly.
Minerva Endocrinol. 2004 Dec;29(4):225-39.
Acromegaly is a slowly developing disfiguring disease characterized by chronic growth hormone (GH) and insulin-like growth factor-I (IGF-I) excess and caused by a pituitary somatotroph adenoma. It is associated to 2- to 3 fold increased mortality, compared to normal population, mostly due to cardiovascular and cerebro-vascular diseases, and to several co-morbid systemic illnesses, such as diabetes mellitus, hypertension, severe arthropathies, a specific cardio-myopathy, goitre, sleep-apnoea, intractable headache. The morbidity and excess mortality of acromegaly are usually the consequence of the metabolic actions of excess GH and IGF-I secretion, while only in rare patients mortality is due to the mass effects of the pituitary tumour. Since, serum IGF-I concentrations within age-adjusted normal range, and a tight GH control have to be achieved to normalize life-expectancy in these patients, an aggressive, and often multi-modality treatment is required for acromegaly. In recent years, new drugs, and new formulations of old drugs, have been developed that are able to effectively inhibit GH secretion or GH action, and may represent important adjuncts or even alternatives to the traditional approaches of surgery and radiotherapy. This review briefly summarizes the therapeutic options nowadays available for acromegaly. A brief note about innovative drugs under study, is also given. [Abstract/Link to Full Text]

Ferone D, Resmini E, Bocca L, Giusti M, Barreca A, Minuto F
Current diagnostic guidelines for biochemical diagnosis of acromegaly.
Minerva Endocrinol. 2004 Dec;29(4):207-23.
Acromegaly is a rare and chronic disease that, in the majority of cases, is due to the presence of a benign growth hormone (GH)-producing tumor of the pituitary. In the past, the diagnosis of acromegaly was established basically on physical changes, and only the patients with a severe clinical picture were brought to medical attention. The development of a radioimmunoassay for detecting GH allowed for the first time to confirm the diagnosis biochemically. Subsequently, methods for measuring insulin-like growth factor 1 (IGF-I) became available and added another important biochemical marker for the diagnosis and follow-up of these patients. Progressive improvements in assay methods have allowed for progressively better definitions of normality and, as a result, have permitted the diagnosis to be biochemically established in patients with only mild forms of the disease. Moreover, new potential markers of disease activity, such as other GH-dependent IGF system parameters, have been investigated and proposed in the diagnostic work-up and for monitoring the therapeutic outcome. Optimal assessment of disease activity, for both diagnostic and follow-up purposes, is mandatory. This subject has been strongly debated regarding proper cut-off values using highly sensitive GH assays as well as the problems linked to IGF system components measurement. Consequently, several consensus reports, as well as original studies, have been issued giving special attention to diagnostic procedures, cut-off revisions and definition of disease activity. The present review discuss principally the biochemical diagnosis of acromegaly based on these articles and on the experience collected in an endocrinological unit considered as reference center for pituitary diseases. [Abstract/Link to Full Text]

Baskin HJ
New applications of thyroid and parathyroid ultrasound.
Minerva Endocrinol. 2004 Dec;29(4):195-206.
In the past decade ultrasound has become an essential part of the examination of the thyroid patient. Sonography of the thyroid has been integrated with the history and physical exam and other thyroid tests (especially needle biopsy) to provide valuable information that has improved patient care. Advances in technology and engineering including high-resolution phased-array transducers, color flow and power Doppler have provided much more detail and information regarding thyroid and neck morphology making diagnosis more accurate. This has expanded the use of ultrasound and resulted in development of new ultrasound applications for both the diagnosis and therapy of thyroid and parathyroid disorders. Ultrasound guidance for needle biopsy of thyroid nodules has become routine. It is now being used to confirm the ultrasound diagnosis of parathyroid adenoma by measuring parathyroid hormone obtained with the needle placed in the lesion under ultrasound guidance. Likewise, non-palpable lymph nodes in the neck discovered by ultrasound and suspected of having metastatic carcinoma can be easily biopsied using ultrasound. The material can be submitted for both cytology and peptide analysis to confirm the diagnosis replacing more expensive imaging. Using these same ultrasound guidance techniques, several groups of investigators have developed methods of therapeutic ablation of tissue by chemical or physical means. This may result in an alternative to surgery for certain thyroid, parathyroid, and lymph node lesions. [Abstract/Link to Full Text]

Rubello D, Pelizzo MR, Gross MD, Fig LM, Shapiro B, Rampin L, Mariani G
Controversies on minimally invasive procedures for radio-guided surgery of parathyroid tumours.
Minerva Endocrinol. 2004 Dec;29(4):189-93.
The definitive treatment of primary hyperparathyroidism (PHPT) is the surgical approach which traditionally consists of bilateral neck exploration with visualization of at least 4 parathyroid glands and removal of the enlarged ones. However, the most frequent cause of PHPT is a solitary parathyroid adenoma so that a limited neck exploration in order to remove the solitary adenoma alone appears adequate to many surgeons. The recent significant improvements achieved in the pre-operative parathyroid localization techniques, mainly the parathyroid scintigraphy, and the introduction in surgical practice of measurement of quick parathyroid hormone, endoscopic procedures, and intra-operative gamma probes used together specific radiopharmaceuticals allowed to offer the PHPT patient a limited neck exploration as the unilateral neck exploration and the minimally invasive parathyroidectomy. The present article deals with the role of the intra-operative gamma probes used together with specific radio-pharmaceuticals, discussing the principal advantages and disadvantages of each currently used radio-guided approach. [Abstract/Link to Full Text]

Schott M, Scherbaum WA
Immunotherapy and gene therapy of thyroid cancer.
Minerva Endocrinol. 2004 Dec;29(4):175-87.
Most forms of thyroid cancer have a good prognosis. Some tumours, however, dedifferentiate and may finally develop into highly malignant anaplastic thyroid carcinomas with a low survival time. Due to their dedifferentiation these tumours are inaccessible to classical therapeutic options as radioiodide treatment or thyrotropin-suppression. Radical surgical revision of the tumour masses is the therapy of choice of patients with limited disease stages including patients with medullary thyroid carcinomas. Despite progress in radiation and chemotherapy regimes, many metastatic forms remain, however, incurable by conventional therapies. During the past few years new developments in immunology have revealed increasing information about the molecular basis of tumour-host interactions. The multitude of information resulting from basic science in cellular immunology, together with the availability of biologic reagents in pharmacological amounts, has opened new venues for the development of immunotherapy approaches for patients with different kind of cancers including thyroid malignancies. This review describes some most important developments in cellular immunotherapies e.g. dendritic cells-based protocols and gene therapy. It also provides a brief overview on the role of cytokines and antibodies in the treatment of advanced thyroid malignancies. [Abstract/Link to Full Text]

Pagano L, Klain M, Pulcrano M, Angellotti G, Pasano F, Salvatore M, Lombardi G, Biondi B
Follow-up of differentiated thyroid carcinoma.
Minerva Endocrinol. 2004 Dec;29(4):161-74.
Thyroid cancer is the most common endocrine malignancy. More than 90% of primary thyroid cancers are differentiated papillary or follicular types. The treatment of differentiated thyroid carcinoma (DTC) consists of total thyroidectomy and radioactive iodine ablation therapy, followed by L-thyroxine therapy. The extent of initial surgery, the indication for radioiodine ablation therapy and the degree of TSH-suppression are all issues that are still being debated cancers are in relation to the risk of recurrence. Total thyroidectomy reduces the risk of recurrence and facilitates (131)I ablation of thyroid remnants. The aim of radioiodine ablation is to destroy any normal or neoplastic residuals of thyroid tissue. These procedures also improve the sensitivity of thyroglobulin (Tg) as a marker of disease, and increase the sensitivity of (131)I total body scan (TBS) for the detection of persistent or recurrent disease. The aim of TSH-suppressive therapy is to restore euthyroidism and to decrease serum TSH levels, in order to reduce the growth and progression of thyroid cancer. After initial treatment, the objectives of the follow-up of DTC is to maintain adequate thyroxine therapy and to detect persistent or recurrent disease through the combined use of neck ultrasound (US) and serum Tg and (131)I TBS after TSH stimulation. The follow-up protocol should be adapted to the risk of recurrence. Recent advances in the follow-up of DTC are related to the use of recombinant human TSH (rhTSH) in order to stimulate Tg production and the ultrasensitive methods for Tg measurement. Undetectable serum Tg during TSH suppressive therapy with L-T4 does not exclude persistent disease, therefore serum Tg should be measured after TSH stimulation. The results of rhTSH administration and L-thyroxine therapy withdrawal are equivalent in detecting recurrent thyroid cancer, but the use of rhTSH helps to avoid the onset of hypothyroid symptoms and the negative effects of acute hypothyroidism on cardiovascular, hepatic, renal and neurological function. In low-risk DTC patients serum Tg after TSH stimulation, together with ultrasound of the neck, should be used to monitor persistent disease, avoiding diagnostic TBS which has a poor sensitivity. These recommendations do not apply when Tg antibodies are present in the serum, in patients with persistent or recurrent disease or limited thyroid surgery. Low-risk patients may be considered to be in remission when undetectable Tg after TSH stimulation and negative US evaluation of the neck are present. On the contrary, detectable Tg after TSH stimulation is an indicator in selecting patients who are candidates for further diagnostic procedures. [Abstract/Link to Full Text]

Biscontini G, Possa M, Sara R, Milella M, Rossetti C
[Diagnostic modalities in patients affected by differentiated thyroid carcinoma with high thyroglobulin levels and total body Iodium-131 negative: PET/CT use after recTSH]
Minerva Endocrinol. 2004 Dec;29(4):151-60.
In the follow-up of differentiated thyroid carcinoma (DTC), after total thyroidectomy and Iodine-131 therapy, thyroglobulin (Tg) levels and Iodine-131 total body have particular importance. The Tg level becomes a specific and very sensitive marker of DTC recurrence: it is usually evaluated after eradication of thyroid residual tissue (by thyroidectomy and radiometabolic therapy), in presence of high level of TSH (>35 microU/ml) obtained with the suspension of therapy or after rec-TSH administration and in absence of anti-Tg antibodies. Usually, to solve diagnostic problems in patients with negative total body Iodine-131 and high levels of thyroglobulin, we consider one or more of the following investigations, on the basis of prognostic factors: radiological examinations (neck US, skeletal X-ray, CT chest and abdomen, MRI) and scintigraphy (bone scintigraphy, Tc-MIBI or Tl-201 scintigraphy, octreoscan, PET/CT). The use of PET is well known in patients in whom carcinoma metastases are strongly suspected and who are unable of concentrating Iodine-131. In order to increase the PET sensitivity, scintigraphy is performed with high TSH levels obtained through a rec-TSH injection on the 1st and 2nd day, PET/CT scan and blood withdrawal (for Tg level evaluation) on the 3rd day. Considering the hypothesis of a recurrence with lesion size below the resolution power of the diagnostic equipment (5 mm), if PET/CT results are negative, the patients are strictly followed-up and Tg is monitored every 4-6 months. An alternative hypothesis might be not to consider the negative-PET patients as sick persons, but to attribute high Tg levels to illegitimate transcription of mRNA for Tg by the non-thyroid cells or to ectopic thyroid tissue (e.g. intrathymus). Positive PET/CT patients are evaluated for a possible surgical removal of the lesions or alternative appropriate therapies. [Abstract/Link to Full Text]

Danzi S, Klein I
Thyroid hormone and the cardiovascular system.
Minerva Endocrinol. 2004 Sep;29(3):139-50.
Thyroid hormone is an important regulator of cardiac function and cardiovascular hemodynamics. Triiodothyronine, (T(3)), the physiologically active form of thyroid hormone, binds to nuclear receptor proteins and mediates the expression of several important cardiac genes, inducing transcription of the positively regulated genes including alpha-myosin heavy chain (MHC) and the sarcoplasmic reticulum calcium ATPase. Negatively regulated genes include beta-MHC and phospholamban, which are down regulated in the presence of normal serum levels of thyroid hormone. T(3) mediated effects on the systemic vasculature include relaxation of vascular smooth muscle resulting in decreased arterial resistance and diastolic blood pressure. In hyperthyroidism, cardiac contractility and cardiac output are enhanced and systemic vascular resistance is decreased, while in hypothyroidism, the opposite is true. Patients with subclinical hypothyroidism manifest many of the same cardiovascular changes, but to a lesser degree than that which occurs in overt hypothyroidism. Cardiac disease states are sometimes associated with the low T(3) syndrome. The phenotype of the failing heart resembles that of the hypothyroid heart, both in cardiac physiology and in gene expression. Changes in serum T(3) levels in patients with chronic congestive heart failure are caused by alterations in thyroid hormone metabolism suggesting that patients may benefit from T(3) replacement in this setting. [Abstract/Link to Full Text]

Loverro G
Polycystic ovary syndrome and cardiovascular disease.
Minerva Endocrinol. 2004 Sep;29(3):129-38.
The aim of the present paper is to analyze recent literature concerning the incidence of cardiovascular complications in women suffering from polycystic ovary syndrome (PCOS). The study takes into consideration all the studies that have been published to date in the international literature in order to clarify whether or not PCOS is able to determine an early onset or whether it is responsible for a higher global incidence of cardiovascular complications in adult age. The main difficulty lies in the absence of prospective studies owing to the long period of time existing between the diagnosis of PCOS and cardiovascular disease which notoriously has a long latency period. Much attention has been paid in the literature, on the other hand, to the analysis of the incidence of cardiovascular risk factors in women suffering from PCOS. Although epidemiological studies have not evidenced an increased incidence of death from cardiovascular events in women suffering from PCOS, the above conclusions might well be invalidated by a patient selection bias, by obsolete diagnostic criteria or by medical or surgical therapies that could influence the outcome of the disease and which are not considered as a confusion factor. Undoubtedly, all the data available up to the present suggest that PCOS possesses the intrinsic conditions that lead to an increased incidence of factors predisposing to cardiovascular diseases. Future longitudinal studies of a prospective nature might be useful for understanding whether the higher incidence of predisposing factors might also lead to greater expectation of cardiovascular events or whether medical therapies or other factors (improvement in endocrine symptomatology with the menopause?) may prevent the increase in the expected incidence of these events. [Abstract/Link to Full Text]

Calderone A
Natriuretic peptides and the management of heart failure.
Minerva Endocrinol. 2004 Sep;29(3):113-27.
Hyperactivation of the renin-angiotensin-aldosterone system (RAAS), heightened sympathetic drive and uncontrolled synthesis of inflammatory cytokines, exacerbates ventricular contractile dysfunction in heart failure patients. The pathophysiological consequences include excessive fluid retention, increased peripheral vascular resistance, and endothelial dysfunction. Consequently, the demand for additional work by the failing myocardium in the presence of a greater afterload cannot be sustained. Therapeutically exploiting the natriuretic peptide system may represent a physiological approach to dampen the deleterious effects of the neuroendocrine systems and inflammatory cytokines. In both patients and animal models of heart failure, pharmacologically increasing plasma natriuretic peptide levels ameliorated vascular tone, renal and endothelial function, and ventricular contractility. Based on these observations, the following review will highlight the therapeutic benefits of the natriuretic peptide system in heart failure. [Abstract/Link to Full Text]

Dunbar RL, Rader DJ
Slaying the metabolic syndrome. Are we battling the Hydra or the Chimera?
Minerva Endocrinol. 2004 Sep;29(3):89-111.
Metabolic syndrome is the latest moniker for an alliance of pathologic conditions that conspire to amplify the risk of atherosclerosis or type 2 diabetes. Several recent advances in the understanding of this condition have led to its widespread adoption in clinical practice, prompted by influential practice guidelines. In particular, guidelines relating to the management of hyperlipidemia and hypertension afford a prominent role for metabolic syndrome, as a risk factor and a target of therapy. In many ways, the scientific evidence base has not kept pace with the demand for treatment options, rendering therapy nebulous. Most prominently, we do not know whether to adopt a strategy based on a multi-pronged attack, or whether to concentrate our greatest efforts on attacking a critical weakness. We review the limited data available regarding metabolic syndrome, with a focus on expert opinion gleaned from clinical guidelines, and offer advice to the clinician from our own experience with this population. [Abstract/Link to Full Text]

Vitale G, Pivonello R, Lombardi G, Colao A
Cardiovascular complications in acromegaly.
Minerva Endocrinol. 2004 Sep;29(3):77-88.
Cardiovascular morbidity and mortality are increased in acromegaly. In fact, GH and IGF-I excess induces a specific cardiomyopathy. The early stage of acromegaly is characterized by the hyperkinetic syndrome (high heart rate and increased systolic output). Frequently, concentric biventricular hypertrophy and diastolic dysfunction occur in acromegaly, leading to an impaired systolic function ending in heart failure if the disease is untreated or unsuccessfully untreated. Besides, abnormalities of cardiac rhythm and of valves have been also described in acromegaly. The coexistence of other complications, such as arterial hypertension and diabetes, aggravates the acromegalic cardiomyopathy. The suppression of GH/IGF-I following an efficacious therapy could decrease left ventricular mass and improve cardiac function. In conclusion, a careful evaluation of cardiac function, morphology and activity seems to be mandatory in acromegaly. [Abstract/Link to Full Text]

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Recent Articles in Reproductive Biology and Endocrinology

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Alviggi C, Revelli A, Anserini P, Ranieri A, Fedele L, Strina I, Massobrio M, Ragni N, De Placido G
A prospective, randomised, controlled clinical study on the assessment of tolerability and of clinical efficacy of Merional (hMG-IBSA) administered subcutaneously versus Merional administered intramuscularly in women undergoing multifollicular ovarian stimulation in an ART programme (IVF).
Reprod Biol Endocrinol. 2007 Dec 4;5(1):45.
ABSTRACT: BACKGROUND: Multifollicular ovarian stimulation (MOS) is widely used in IVF and the compliance to treatment is deeply influenced by the tolerability of the medication(s) used and by the ease of self-administration. This prospective, controlled, randomised, parallel group open label, multicenter, phase III, equivalence study has been aimed to compare the clinical effectiveness (in terms of oocytes obtained) and tolerability of subcutaneous (s.c.) self-administered versus classical intramuscular (i.m.) injections of Merional, a new highly-purified hMG preparation. METHODS: A total of 168 normogonadotropic women undergoing IVF were enrolled. Among them, 160 achieved pituitary suppression with a GnRH-agonist long protocol and were randomised to MOS treatment with Merional s.c. or i.m. They started MOS with a standard hMG dose between 150-300 IU, depending upon patient's age, and underwent a standard IVF procedure. RESULTS: No statistically significant difference in the mean number of collected oocytes (primary endpoint) was observed between the two study subgroups (7.46, SD 4.24 vs. 7.86, SD 4.28 in the s.c. and i.m. subgroups, respectively). As concerns the secondary outcomes, both the pregnancy and the clinical pregnancy rates were comparable between subgroups. The incidence of adverse events was similar in the two groups (2.4% vs. 3.7%, respectively). Pain at injection site was reported only the i.m. group (13.9% of patients). CONCLUSIONS: Merional may be used by s.c. injections in IVF with an effectiveness in terms of retrieved oocytes that is equivalent to the one obtained with i.m administration and with a better local tolerability. With the limitations due to the sample size af this study, s.c. and i.m. administration routes seem to have the same overall safety. [Abstract/Link to Full Text]

Dimitriadis E, Sharkey AM, Tan YL, Salamonsen LA, Sherwin JR
Immunolocalisation of phosphorylated STAT3, interleukin 11 and leukaemia inhibitory factor in endometrium of women with unexplained infertility during the implantation window.
Reprod Biol Endocrinol. 2007 Nov 29;5(1):44.
ABSTRACT: BACKGROUND: Uterine receptivity and embryo implantation are critical in the establishment of pregnancy. The diagnosis of endometrial fertility requires more precise measurements of endometrial receptivity. Interleukin (IL-11) and leukemia inhibitory factor (LIF) are essential for murine implantation and signal via intracellular phosphorylation (p) of STAT3 in the endometrium. Both cytokines are present in the endometrium of women duiring the receptive window. Endometrial IL-11, IL-11 receptor alpha (IL-11Ralpha), LIF and pSTAT3 in women with primary unexplained infertility was compared to normal fertile women during the implantation window. METHODS: LH timed endometrial biopsies (LH+6 to LH+10) were collected from women with unexplained infertility and normal fertility. pSTAT3, IL-11, IL-11Ralpha and LIF production was determined by immunohistochemistry. Staining intensity was determoned by two independent observers blind to the fertility status of the patient from whom the biopsy was taken. Staining intensity and heterogeneity in each of the endometrial compartments (epithelium; stroma, including decidualized stromal cells; and vasculature) was assessed. The Mann-Whitney U test was used to analyze IL-11, pSTAT3, IL-11Ralpha and LIF immunostaining intensities in the samples. RESULTS: IL-11, IL-11Ralpha and LIF were present predominantly in glandular epithelium, whilst luminal epithelium showed patchy staining. pSTAT3 was present in both glandular epithelium and stroma. IL-11 and pSTAT3 immunostaining was significantly lower in glandular epithelium in infertile women compared to controls (P<0.05) whilst IL-11Ralpha and LIF staining did not differ. CONCLUSION: This is the first demonstration of reduced endometrial pSTAT3 and IL-11 in some women with unexplained infertility. This suggests IL-11 and pSTAT3 may be involved in the secretory transformation of glandular epithelium during receptivity. Reduced IL-11 production and STAT3 phosphorylation may contribute to unexplained infertility in some women. [Abstract/Link to Full Text]

Teerds KJ, van Dissel-Emiliani FM, De Miguel MP, de Boer-Brouwer M, Korting LM, Rijntjes E
Oncostatin-M inhibits luteinizing hormone stimulated Leydig cell progenitor formation in vitro.
Reprod Biol Endocrinol. 2007 Nov 8;5(1):43.
ABSTRACT: BACKGROUND: The initial steps of stem Leydig cell differentiation into steroid producing progenitor cells are thought to take place independent of luteinizing hormone (LH), under the influence of locally produced factors such as leukemia inhibitory factor (LIF), platelet derived growth factor A and stem cell factor. For the formation of a normal sized Leydig cell population in the adult testis, the presence of LH appears to be essential. Oncostatin M (OSM) is a multifunctional cytokine and member of the interleukin (IL)-6 family that also includes other cytokines such as LIF. In the rat OSM is highly expressed in the late fetal and neonatal testis, and may thus be a candidate factor involved in progenitor formation. METHODS: Interstitial cells were isolated from 13-day-old rat testes and cultured for 1, 3 or 8 days in the presence of different doses of OSM (range: 0.01 to 10 ng/ml) alone or in combination with LH (1 ng/ml). The effects of OSM and LH on cell proliferation were determined by incubating the cultures with [3H]thymidine or bromodeoxyuridine (BrdU). Developing progenitor cells were identified histochemically by the presence of the marker enzyme 3beta-hydroxysteroid dehydrogenase (3beta-HSD). RESULTS: OSM, when added at a dose of 10 ng/ml, caused a nearly 2-fold increase in the percentage of Leydig cell progenitors after 8 days of culture. Immunohistochemical double labelling experiments with 3beta-HSD and BrdU antibodies showed that this increase was the result of differentiation of stem Leydig cells/precursor cells and not caused by proliferation of progenitor cells themselves. The addition of LH to the cultures consistently resulted in an increase in progenitor formation throughout the culture period. Surprisingly, when OSM and LH were added together, the LH induced rise in progenitor cells was significantly inhibited after 3 and 8 days of culture. CONCLUSION: Taken together, the results of the present study suggest that locally produced OSM may not only play a role in the regulation of Sertoli cell proliferation and the initiation of spermatogenesis but may also play a role in the regulation of Leydig cell progenitor formation by keeping the augmenting effects of LH on this process in abeyance. [Abstract/Link to Full Text]

Oberley RE, Goss KL, Quintar AA, Maldonado CA, Snyder JM
Regulation of surfactant protein D in the rodent prostate.
Reprod Biol Endocrinol. 2007 Nov 7;5(1):42.
ABSTRACT: BACKGROUND: Surfactant protein D (SP D) is an innate immune protein that is present in mucosal lined surfaces throughout the human body, including the male reproductive tract. In the present study, we characterized the regulation of SP D expression in the mouse and rat prostate. METHODS: Real time reverse transcriptase polymerase chain reaction (RT-PCR) and immunostaining were used to characterize SP-D mRNA and protein in the male reproductive tract of the mouse. In order to evaluate the effects of testosterone on SP-D gene expression, we measured SP-D mRNA levels via real time RT PCR in prostates from sham-castrated mice and castrated mice. In addition, we used a rat prostatitis model in which Escherichia coli was injected into the prostate in vivo to determine if infection influences SP-D protein levels in the prostate. RESULTS: We found that SP-D mRNA and protein are present throughout the mouse male reproductive tract, including in the prostate. We determined that castration increases prostate SP-D mRNA levels (~7 fold) when compared to levels in sham-castrated animals. Finally, we demonstrated that infection in the prostate causes a significant increase in SP-D content 24 and 48 hours post-infection. CONCLUSIONS: Our results suggest that infection and androgens regulate SP-D in the prostate. [Abstract/Link to Full Text]

Smith RC, McClure MC, Smith MA, Abel PW, Bradley ME
The role of voltage-gated potassium channels in the regulation of mouse uterine contractility.
Reprod Biol Endocrinol. 2007 Nov 2;5(1):41.
ABSTRACT: BACKGROUND: Uterine smooth muscle cells exhibit ionic currents that appear to be important in the control of uterine contractility, but how these currents might produce the changes in contractile activity seen in pregnant myometrium has not been established. There are conflicting reports concerning the role of voltage-gated potassium (Kv) channels and large-conductance, calcium-activated potassium (BK) channels in the regulation of uterine contractility. In this study we provide molecular and functional evidence for a role for Kv channels in the regulation of spontaneous contractile activity in mouse myometrium, and also demonstrate a change in Kv channel regulation of contractility in pregnant mouse myometrium. METHODS: Functional assays which evaluated the effects of channel blockers and various contractile agonists were accomplished by quantifying contractility of isolated uterine smooth muscle obtained from nonpregnant mice as well as mice at various stages of pregnancy. Expression of Kv channel proteins in isolated uterine smooth muscle was evaluated by Western blots. RESULTS: The Kv channel blocker 4-aminopyridine (4-AP) caused contractions in nonpregnant mouse myometrium (EC50 = 54 micromolar, maximal effect at 300 micromolar) but this effect disappeared in pregnant mice; similarly, the Kv4.2/Kv4.3 blocker phrixotoxin-2 caused contractions in nonpregnant, but not pregnant, myometrium. Contractile responses to 4-AP were not dependent upon nerves, as neither tetrodotoxin nor storage of tissues at room temperature significantly altered these responses, nor were responses dependent upon the presence of the endometrium. Spontaneous contractions and contractions in response to 4-AP did not appear to be mediated by BK, as the BK channel-selective blockers iberiotoxin, verruculogen, or tetraethylammonium failed to affect either spontaneous contractions or 4-AP-elicited responses. A number of different Kv channel alpha subunit proteins were found in isolated myometrium from both nonpregnant and term-pregnant mice, and one of these proteins - Kv4.3 - was found to disappear in term-pregnant tissues. CONCLUSIONS: These findings suggest a role for Kv channels in the regulation of uterine contractility, and that changes in the expression and/or function of specific Kv channels may account for the functional changes seen in pregnant myometrium. [Abstract/Link to Full Text]

Rey-Ares V, Lazarov N, Berg D, Berg U, Kunz L, Mayerhofer A
Dopamine receptor repertoire of human granulosa cells.
Reprod Biol Endocrinol. 2007 Oct 25;5(1):40.
ABSTRACT: BACKGROUND: High levels of dopamine (DA) were described in human ovary and recently evidence for DA receptors in granulosa and luteal cells has been provided, as well. However, neither the full repertoire of ovarian receptors for DA, nor their specific role, is established. Human granulosa cells (GCs) derived from women undergoing in vitro fertilization (IVF) are an adequate model for endocrine cells of the follicle and the corpus luteum and were therefore employed in an attempt to decipher their DA receptor repertoire and functionality. METHODS: Cells were obtained from patients undergoing IVF and examined using cDNA-array, RT-PCR, Western blotting and immunocytochemistry. In addition, calcium measurements (with FLUO-4) were employed. Expression of two DA receptors was also examined by in-situ hybridization in rat ovary. Effects of DA on cell viability and cell volume were studied by using an ATP assay and an electronic cell counter system. RESULTS: We found members of the two DA receptor families (D1- and D2 -like) associated with different signaling pathways in human GCs, namely D1 (as expected) and D5 (both are Gs coupled and linked to cAMP increase) and D2, D4 (Gi/Gq coupled and linked to IP3/DAG). D3 was not found. The presence of the trophic hormone hCG (10 IU/ml) in the culture medium for several days did not alter mRNA (semiquantitative RT-PCR) or protein levels (immunocytochemistry/Western blotting) of D1,2,4,5 receptors. Expression of prototype receptors for the two families, D1 and D2 was furthermore shown in rat granulosa and luteal cells by in situ hybridization. Among the DA receptors found in human GCs, D2 expression was marked both at mRNA and protein levels and it was therefore further studied. Results of additional RT-PCR and Western blots showed two splice variants (D2L, D2S). Irrespective of these variants, D2 proved to be functional, as DA raised intracellular calcium levels. This calcium mobilizing effect of DA was observed in the absence of extracellular calcium and was abolished by a D2 blocker (L-741,626). DA treatment (48 h) of human GCs resulted in slightly, but significantly enlarged, viable cells. CONCLUSIONS: A previous study showed D1 in human GCs, which are linked to cAMP, and the present study reveals the full spectrum of DA receptors present in these endocrine cells, which also includes D2-like receptors, linked to calcium. Ovarian DA can act thus via D1,2,4,5, which are co-expressed by endocrine cells of the follicle and the corpus luteum and are linked to different signaling pathways. This suggests a complex role of DA in the regulation of ovarian processes. [Abstract/Link to Full Text]

Chandrakanthan V, Chami O, Stojanov T, O'Neill C
Variable expressivity of the tumour suppressor protein TRP53 in cryopreserved human blastocysts.
Reprod Biol Endocrinol. 2007;539.
In a mouse model, in vitro fertilization or extended embryo culture leads to the increased expression of TRP53 in susceptible embryos. Ablation of the TRP53 gene improved embryo viability indicating that increased expression of TRP53 is a cause of the reduction of embryo viability resulting from in vitro fertilization or embryo culture. This study investigates the status of TRP53 expression in human embryos produced by intracytoplasmic sperm injection. Following fertilization, embryos were cultured for 96 h and then cryopreserved. Immediately upon thawing they were fixed in formaldehyde and subjected to immunostaining for TRP53. Staining was visualized by confocal microscopy. Negative controls were incubated with isotype control immunoglobulin and showed negligible staining. All embryos showed TRP53 staining above negative controls. TRP53 staining was heterogenous within and between embryos. An embryo that showed retarded development showed high levels of TRP53 expression. A blastocyst that had a collapsed blastocoel also showed high levels of TRP53 compared to morphologically normal blastocysts. Most TRP53 staining was in the region of the nucleus. Morphologically normal blastocysts tended to show little nuclear accumulation of stain. However, some cells within these embryos had high levels of nuclear TRP53 expression. The results show that embryos have varying sensitivity to the stresses of production and culture in vitro, and this resulted in variable expressivity of TRP53. [Abstract/Link to Full Text]

Dery MC, Van Themsche C, Provencher D, Mes-Masson AM, Asselin E
Characterization of EN-1078D, a poorly differentiated human endometrial carcinoma cell line: a novel tool to study endometrial invasion in vitro.
Reprod Biol Endocrinol. 2007;538.
BACKGROUND: To date, tools to study metastasis in endometrial cancers are insufficiently developed. The aim of this study was to characterize the cell line EN-1078D, a new endometrial carcinoma cell line derived from a metastasis to the ovary. METHODS AND RESULTS: Cells were characterized using cytology, transmission electron microscopy, karyotyping and morphological appearance in culture. Molecular features were determined by RT-PCR, Western Blot, FISH and sequencing. MTT proliferation assays were performed to investigate the sensitivity of EN-1078D to anticancer agents such as cisplatin and doxorubicin. Also, subcutaneous and intravenous injections in nude mice were done to test the tumorigenic and metastatic properties of EN-1078D cells. Our results indicate that EN-1078D cells express both oestrogen receptors isoforms (ER alpha and ER beta) and also low levels of progesterone receptor B (PR-B). In addition, this cell line expresses high levels of MMP-2 and MMP-14 mRNA, low levels of TIMP-1 and TIMP-2 transcripts and no detectable levels of MMP-9 mRNA. Moreover, all nude mice developed tumors by subcutaneous injections and cell invasion was observed in vitro in response to TGF-beta 3. Her-2/neu was not overamplified but mutations in the C-2 domain of PTEN gene as well as codon 12 of the K-Ras gene were found. Finally, EN-1078D shows sensitivity to drugs commonly used in chemotherapy such as cisplatin and doxorubicin: IC50 of 2.8 microM of cisplatin after 72 hours of exposure and 0.54 microM of doxorubicin after 48 hours. CONCLUSION: Taken together, these results suggest that EN-1078D will be an excellent tool to study the properties of metastatic endometrial cancer cells in vitro and their regulation by sex steroids. [Abstract/Link to Full Text]

Goravanahally MP, Sen A, Inskeep EK, Flores JA
PKC epsilon and an increase in intracellular calcium concentration are necessary for PGF2 alpha to inhibit LH-stimulated progesterone secretion in cultured bovine steroidogenic luteal cells.
Reprod Biol Endocrinol. 2007;537.
The hypotheses that PKC epsilon is necessary for: 1) PGF2 alpha to inhibit LH-stimulated progesterone (P4) secretion, and 2) for the expression of key prostaglandin synthesizing/metabolizing enzymes were tested in bovine luteal cells in which PKC epsilon expression had been ablated using a validated siRNA protocol. Steroidogenic cells from Day -6 bovine corpus luteum (CL) were isolated and transfected to reduce PKC epsilon expression after 48, 72 and 96 h. A third tested hypothesis was that an increase in intracellular calcium concentration ([Ca(2+)]i) is the cellular mechanism through which PGF2 alpha inhibits luteal progesterone. The hypothesis was tested with two pharmacological agents. In the first test, the dose-dependent effects on raising the [Ca(2+)]i with the ionophore, A23187, on basal and LH-stimulated P4 secretion in cells collected from early (Day -4) and mid-cycle (Day -10) bovine CL was examined. In the second test, the ability of PGF2 alpha to inhibit LH-stimulated P4 secretion in Day-10 luteal cells was examined under conditions in which an elevation in [Ca(2+)]i had been buffered by means of the intracellular calcium chelator, Bapta-AM.PKC epsilon expression was reduced 65 and 75% by 72 and 96 h after transfection, respectively. In cells in which PKC epsilon expression was ablated by 75%, the inhibitory effect of PGF2 alpha on LH-stimulated P4 secretion was only 29% lower than in the LH-stimulated group. In contrast, it was reduced by 75% in the group where PKC epsilon expression had not been reduced (P < 0.05). Real time PCR analysis indicated that there were no differences in the expression of cyclooxygenase-2 (COX-2), aldoketoreductase 1B5 (AKR1B5), prostaglandin E synthase (PGES), hydroxyprostaglandin-15 dehydrogenase (PGDH) and PGE2 -9-reductase as a function of PKC epsilon down-regulation. Finally, LH stimulated secretion of P4 at each luteal stage (Day -4 and -10), and PGF2 alpha inhibited this only in Day -10 cells (P < 0.05). When A23187 was used at concentrations greater than 0.1 mumol, the induced elevation in [Ca(2+)]i inhibited the effect of LH on secretion of P4 in Day -4 and -10 cells (P < 0.05, Fig. 5). The inhibitory effect of PGF2 alpha on LH-stimulated P4 in Day -10 cells was reduced if an increase in [Ca(2+)]i was prevented with Bapta-AM. These results support the hypothesis that differential expression of PKC epsilon and an elevation of [Ca(2+)]i are important for acquisition of luteolytic response to PGF2 alpha. [Abstract/Link to Full Text]

Angelopoulou R, Plastira K, Msaouel P
Spermatozoal sensitive biomarkers to defective protaminosis and fragmented DNA.
Reprod Biol Endocrinol. 2007;536.
ABSTRACT: Human sperm DNA damage may have adverse effects on reproductive outcome. Infertile men possess substantially more spermatozoa with damaged DNA compared to fertile donors. Although the extent of this abnormality is closely related to sperm function, the underlying etiology of ensuing male infertility is still largely controversial. Both intra-testicular and post-testicular events have been postulated and different mechanisms have been proposed to explain the presence of damaged DNA in human spermatozoa. Three among them, i.e. abnormal chromatin packaging, oxidative stress and apoptosis, are the most studied and discussed in the present review. Furthermore, results from numerous investigations are presented, including our own findings on these pathological conditions, as well as the techniques applied for their evaluation. The crucial points of each methodology on the successful detection of DNA damage and their validity on the appraisal of infertile patients are also discussed. Along with the conventional parameters examined in the standard semen analysis, evaluation of damaged sperm DNA seems to complement the investigation of factors affecting male fertility and may prove an efficient diagnostic tool in the prediction of pregnancy outcome. [Abstract/Link to Full Text]

Luo X, Pan Q, Liu L, Chegini N
Genomic and proteomic profiling II: comparative assessment of gene expression profiles in leiomyomas, keloids, and surgically-induced scars.
Reprod Biol Endocrinol. 2007;535.
BACKGROUND: Leiomyoma have often been compared to keloids because of their fibrotic characteristic and higher rate of occurrence among African Americans as compared to other ethnic groups. To evaluate such a correlation at molecular level this study comparatively analyzed leiomyomas with keloids, surgical scars and peritoneal adhesions to identify genes that are either commonly and/or individually distinguish these fibrotic disorders despite differences in the nature of their development and growth. METHODS: Microarray gene expression profiling and realtime PCR. RESULTS: The analysis identified 3 to 12% of the genes on the arrays as differentially expressed among these tissues based on P ranking at greater than or equal to 0.005 followed by 2-fold cutoff change selection. Of these genes about 400 genes were identified as differentially expressed in leiomyomas as compared to keloids/incisional scars, and 85 genes as compared to peritoneal adhesions (greater than or equal to 0.01). Functional analysis indicated that the majority of these genes serve as regulators of cell growth (cell cycle/apoptosis), tissue turnover, transcription factors and signal transduction. Of these genes the expression of E2F1, RUNX3, EGR3, TBPIP, ECM-2, ESM1, THBS1, GAS1, ADAM17, CST6, FBLN5, and COL18A was confirmed in these tissues using quantitative realtime PCR based on low-density arrays. CONCLUSION: the results indicated that the molecular feature of leiomyomas is comparable but may be under different tissue-specific regulatory control to those of keloids and differ at the levels rather than tissue-specific expression of selected number of genes functionally regulating cell growth and apoptosis, inflammation, angiogenesis and tissue turnover. [Abstract/Link to Full Text]

Pan Q, Luo X, Chegini N
Genomic and proteomic profiling I: Leiomyomas in African Americans and Caucasians.
Reprod Biol Endocrinol. 2007;534.
BACKGROUND: Clinical observations indicate that leiomyomas occur more frequently in African Americans compared to other ethnic groups with unknown etiology. To identify the molecular basis for the difference we compared leiomyomas form A. Americans with Caucasians using genomic and proteomic strategies. METHODS: Microarray, realtime PCR, 2D-PAGE, mass spectrometry, Western blotting and immunohistochemistry. RESULTS: Using Affymetrix U133A array and analysis based on P ranking (P < 0.01) 1470 genes were identified as differentially expressed in leiomyomas compared to myometrium regardless of ethnicity. Of these, 268 genes were either over-expressed (177 genes) or under-expressed (91 genes) based on P < 0.01 followed by 2-fold cutoff selection in leiomyomas of A. Americans as compared to Caucasians. Among them, the expression E2F1, RUNX3, EGR3, TBPIP, ECM2, ESM1, THBS1, GAS1, ADAM17, CST6, CST7, FBLN5, ICAM2, EDN1 and COL18 was validated using realtime PCR low-density arrays. 2D PAGE coupled with image analysis identified 332 protein spots of which the density/volume of 31 varied by greater than or equal to 1.5 fold in leiomyomas as compared to myometrium. The density/volume of 34 protein-spots varied by greater than or equal to 1.5 fold (26 increased and 8 decreased) in leiomyomas of A. Americans as compared to Caucasians. Tandem mass spectrometric analysis of 15 protein spots identified several proteins whose transcripts were also identified by microarray, including 14-3-3 beta and mimecan, whose expression was confirmed using western blotting and immunohistochemistry. CONCLUSION: These findings imply that the level rather than the ethnic-specific expression of a number of genes and proteins may account for the difference between leiomyomas and possibly myometrium, in A. Americans and Caucasians. Further study using larger sample size is required to confirm these findings. [Abstract/Link to Full Text]

Tauck SA, Olsen JR, Berardinelli JG
Adrenal involvement in the biostimulatory effect of bulls.
Reprod Biol Endocrinol. 2007;533.
BACKGROUND: The objective was to evaluate if cortisol concentrations are associated with the resumption of luteal activity in postpartum, primiparous cows exposed to bulls. The hypotheses were that 1) interval from start of exposure to resumption of luteal activity; 2) proportions of cows that resumed luteal function during the exposure period; and 3) cortisol concentrations do not differ among cows exposed or not exposed to bulls (Exp. 1), and cows continuously exposed to bull or steer urine (Exp. 2). METHODS: In Exp. 1, 28 anovular cows were exposed (BE; n = 13) or not exposed (NE; n = 15) to bulls for 30 d at 58 d after calving. In Exp. 2, 38 anovular cows were fitted with a controlled urine delivery device at 45 d after calving and exposed continuously (24 h/d) to bull (BUE; n = 19) or steer (SUE; n = 19) urine. Length of exposure was ~64 d. Blood samples were collected from each cow on D 0 and every 3 d throughout exposure periods in both experiments and assayed for progesterone. Cortisol was assayed in samples collected on D 0, 8, 16, and 24 in Exp. 1; and, D 0, 19, 38, and 57 in Exp. 2. RESULTS: In Exp. 1, interval from the start of exposure to resumption of luteal activity was shorter (P < 0.05) for BE cows than NE cows, similarly, more (P < 0.05) BE cows than NE cows resumed luteal function during the exposure period. In Exp. 2, there was no difference in intervals from the start of exposure to resumption of luteal activity and proportions of cows that resumed luteal function during the exposure period between BUE and SUE cows. In Exp. 1, there was no difference in cortisol concentrations between BE and NE cows at the start of the experiment (D 0), however, cortisol concentrations were greater (P < 0.05) in BE cows than NE cows on D 9, 18, and 27. In Exp. 2, cortisol concentrations were higher for BUE than SUE cows on D 0 (P < 0.05), thereafter cortisol decreased (P < 0.05) but did not differ between BUE and SUE cows. CONCLUSION: We conclude that the physical presence of bulls stimulates resumption of luteal activity and is coincident with increased cortisol concentrations, and hypothesize a possible association between adrenal activation and the biostimulatory effect of bulls. [Abstract/Link to Full Text]

Kassab A, Sabatini L, Lieberman G, Tozer A, Zosmer A, Davis C, Al-Shawaf T
Does measuring early basal serum follicular luteinising [correction of lutinising] hormone assist in predicting in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) outcome?
Reprod Biol Endocrinol. 2007;532.
BACKGROUND: The aim was to examine the correlation of early follicular serum lutinising hormone (LH) and the clinical outcome of assisted reproduction technique (ART). METHODS: An observational study included 1333 consecutive women undergoing in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). 964 women were having their first cycle of ART. Data were entered prospectively. All women had serum LH measured in the 6 months before the index cycle studied. No repeat cycles were included. The main outcomes measured were clinical pregnancy (CP) and live birth (LB) correlation to serum LH. Forward multivariate stepwise regression analysis was applied, and other statistical tests were used as appropriate. RESULTS: There was non significant correlation between basal serum LH and CP and LB in the polycystic ovary syndrome group (R2 = 0.02, F = 1.7 and P = 0.76) (R2 = 0.01, F = 2.6 and P = 0.77) respectively after adjusting for age, BMI, day of oocyte retrieval, starting dose, total dose of stimulation, type of gonadotrophin used, number of oocytes retrieved, fertilization rate and number of embryos transferred. Other aetiological causes group there was similarly non significant correlation between basal serum LH and CP (R2 = 0.05, F = 13.1 and P = 0.66), nor for LB (R2 = 0.007, F = 4.5 and P = 0.9). CONCLUSION: Early follicular serum LH measurements in the 6 months before IVF/ICSI treatment cycle did not correlate with the clinical pregnancy or the live birth rate. [Abstract/Link to Full Text]

Zannoni A, Bernardini C, Rada T, Ribeiro LA, Forni M, Bacci ML
Prostaglandin F2-alpha receptor (FPr) expression on porcine corpus luteum microvascular endothelial cells (pCL-MVECs).
Reprod Biol Endocrinol. 2007;531.
BACKGROUND: The corpus luteum (CL) is a transient endocrine gland and prostaglandin F2-alpha is considered to be the principal luteolysin in pigs. In this species, the in vivo administration of prostaglandin F2-alpha induces apoptosis in large vessels as early as 6 hours after administration. The presence of the prostaglandin F2-alpha receptor (FPr) on the microvascular endothelial cells (pCL-MVECs) of the porcine corpus luteum has not yet been defined. The aim of the study was to assess FPr expression in pCL-MVECs in the early and mid-luteal phases (EL-p, ML-p), and during pregnancy (P-p). Moreover, the effectiveness of prostaglandin F2-alpha treatment in inducing pCL-MVEC apoptosis was tested. METHODS: Porcine CLs were collected in the EL and ML phases and during P-p. All CLs from each animal were minced together and the homogenates underwent enzymatic digestion. The pCL-MVECs were then positively selected by an immunomagnetic separation protocol using Dynabeads coated with anti-CD31 monoclonal antibody and seeded in flasks in the presence of EGM 2-MV (Microvascular Endothelial Cell Medium-2). After 4 days of culture, the cells underwent additional immunomagnetic selection and were seeded in flasks until the confluent stage.PCR Real time, western blot and immunodetection assays were utilized to assess the presence of FPr on pCL-MVEC primary cultures. Furthermore, the influence of culture time (freshly isolated, cultured overnight and at confluence) and hormonal treatment (P4 and E2) on FPr expression in pCL-MVECs was also investigated. Apoptosis was detected by TUNEL assay of pCL-MVECs exposed to prostaglandin F2-alpha. RESULTS: We obtained primary cultures of pCL-MVECs from all animals. FPr mRNA and protein levels showed the highest value (ANOVA) in CL-MVECs derived from the early-luteal phase. Moreover, freshly isolated MVECs showed a higher FPr mRNA value than those cultured overnight and confluent cells (ANOVA). prostaglandin F2-alpha treatment failed to induce an apoptotic response in all the pCL-MVEC cultures. CONCLUSION: Our data showing the presence of FPr on MVECs and the inability of prostaglandin F2-alpha to evoke an in vitro apoptotic response suggest that other molecules or mechanisms must be considered in order to explain the in vivo direct pro-apoptotic effect of prostaglandin F2-alpha at the endothelial level. [Abstract/Link to Full Text]

Drolet R, Simard M, Plante J, Laberge P, Tremblay Y
Human type 2 17 beta-hydroxysteroid dehydrogenase mRNA and protein distribution in placental villi at mid and term pregnancy.
Reprod Biol Endocrinol. 2007;530.
BACKGROUND: During human pregnancy, the placental villi produces high amounts of estradiol. This steroid is secreted by the syncytium, which is directly in contact with maternal blood. Estradiol has to cross placental foetal vessels to reach foetal circulation. The enzyme 17beta-hydroxysteroid dehydrogenase type 2 (17beta-HSD2) was detected in placental endothelial cells of foetal vessels inside the villi. This enzyme catalyzes the conversion of estradiol to estrone, and of testosterone to androstenedione. It was proposed that estradiol level into foetal circulation could be regulated by 17beta-HSD2. METHODS: We obtained placentas from 10 to 26 6/7 weeks of pregnancy from women undergoing voluntary termination of pregnancy, term placentas were collected after normal spontaneous vaginal deliveries. We quantified 17beta-HSD2 mRNA levels in mid-gestation and term human placenta by RT-QPCR. We produced a new anti-17beta-HSD2 antibody to study its spatio-temporal expression by immunohistochemistry. We also compared steroid levels (testosterone, estrone and estradiol) and 17beta-HSD2 mRNA and protein levels between term placenta and endometrium. RESULTS: High 17beta-HSD2 mRNA and protein levels were found in both mid-gestation and term placentas. However, we showed that 17beta-HSD2 mRNA levels increase by 2.27 fold between mid-gestation and term. This period coincides with a transitional phase in the development of the villous vasculature. In mid-gestation placenta, high levels of 17beta-HSD2 were found in mesenchymal villi and immature intermediate villi, more precisely in endothelial cells of the stromal channel. At term, high levels of 17beta-HSD2 were found in the numerous sinusoidal capillaries of terminal villi. 17beta-HSD2 mRNA and protein levels in term placentas were respectively 25.4 fold and 30 to 60 fold higher than in the endometrium. Steroid levels were also significantly higher in term placenta than in the endometrium. CONCLUSION: The spatial and temporal expression of 17beta-HSD2 in the placenta during pregnancy and the comparison of 17beta-HSD2 expression and steroid levels between placental villi and endometrium are compatible with a role in the modulation of active and inactive forms of estrogens. Our observations strongly support the hypothesis that 17beta-HSD2 acts as a barrier decreasing estradiol secretion rates in the foetal circulation. [Abstract/Link to Full Text]

Filonzi M, Cardoso LC, Pimenta MT, Queiróz DB, Avellar MC, Porto CS, Lazari MF
Relaxin family peptide receptors Rxfp1 and Rxfp2: mapping of the mRNA and protein distribution in the reproductive tract of the male rat.
Reprod Biol Endocrinol. 2007;529.
BACKGROUND: Relaxin is the endogenous ligand of the G-protein coupled receptor RXFP1, previously known as LGR7. In humans relaxin can also activate, but with lower affinity, the closely related receptor for the insulin-like peptide from Leydig cells, RXFP2, previously known as LGR8. The lack of relaxin impairs male fertility but the precise distribution and the function of relaxin receptors in the male reproductive tract is not known. We investigated the distribution of Rxfp1 and Rxfp2 in the reproductive tract of the male rat and the function of relaxin in the vas deferens, a tissue with high expression of both receptors. METHODS: The presence of mRNA for Rxfp1 and Rxfp2 was investigated in testes, cultured Sertoli cells, epididymis, vas deferens, seminal vesicle, prostate, and spermatozoa by RT-PCR and Southern blot. Protein expression in the testis, vas deferens, primary culture of Sertoli cells, and spermatozoa was assessed by immunohistochemistry and immunofluorescence. The role of relaxin in the vas deferens was evaluated by contractility studies and radioimmunoassay of cAMP production. The effect of relaxin on mRNA levels for metalloproteinase-7 was measured by Northern blot. RESULTS: Transcripts for Rxfp1 and Rxfp2 were present in almost all parts of the male reproductive tract, with high levels in testis and vas deferens. Both receptors were immunolocalized in late stage germ cells but not in mature spermatozoa, although mRNAs for both receptors were also present in mature spermatozoa. Rxfp1 but not Rxfp2 was detected in cultured Sertoli cells. Strong immunostaining for Rxfp1 and Rxfp2 was seen in muscular and epithelial layers of the vas deferens and in arteriolar walls. Relaxin did not affect contractility and cyclic AMP production of the vas deferens, but increased the levels of mRNA for metalloproteinase-7. CONCLUSION: Rxfp1 and Rxfp2 are widely and similarly distributed throughout the male reproductive tract. Our results suggest that Rxfp1 on spermatids and Sertoli cells may be important in spermatogenesis. Relaxin in the vas deferens does not affect contractility, but may affect vascular compliance and collagen and matrix remodeling. [Abstract/Link to Full Text]

Zhao B, Koon D, Curtis AL, Soper J, Bethin KE
Identification of 9 uterine genes that are regulated during mouse pregnancy and exhibit abnormal levels in the cyclooxygenase-1 knockout mouse.
Reprod Biol Endocrinol. 2007;528.
BACKGROUND: Preterm birth is the leading cause of all infant mortality. In 2004, 12.5% of all births were preterm. In order to understand preterm labor, we must first understand normal labor. Since many of the myometrial changes that occur during pregnancy are similar in mice and humans and mouse gestation is short, we have studied the uterine genes that change in the mouse during pregnancy. Here, we used microarray analysis to identify uterine genes in the gravid mouse that are differentially regulated in the cyclooxygenase-1 knockout mouse model of delayed parturition. METHODS: Gestational d18.0 uteri (n = 4) were collected from pregnant wild-type and cyclooxygenase-1 knockout mice. Part of the uterus was used for frozen sections and RNA was isolated from the remainder. Microarray analysis was performed at the Indiana University School of Medicine Genomic Core and analyzed using the Microarray Data Portal. Northern analysis was performed to confirm microarray data and the genes localized in the gravid uterus by in situ hybridization. RESULTS: We identified 277 genes that are abnormally expressed in the gravid d18.0 cyclooxygenase-1 knockout mouse. Nine of these genes are also regulated in the normal murine uterus during the last half of gestation. Many of these genes are involved in the immune response, consistent with an important role of the immune system in parturition. Expression of 4 of these genes; arginase I, IgJ, Tnfrsf9 and troponin; was confirmed by Northern analysis to be mis-regulated during pregnancy in the knockout mouse. In situ hybridization of these genes demonstrated a similar location in the gravid wild-type and Cox-1 knockout mouse uteri. CONCLUSION: To our knowledge, this is the first work to demonstrate the uterine location of these 4 genes in the mouse during late pregnancy. There are several putative transcription factor binding sites that are shared by many of the 9 genes identified here including; estrogen and progesterone response elements and Ets binding sites. In summary, this work identifies 9 uterine murine genes that may play a role in parturition. The function of these genes is consistent with an important role of the immune system in parturition. [Abstract/Link to Full Text]

Corthorn J, Rey S, Chacón C, Valdés G
Spatio-temporal expression of MMP-2, MMP-9 and tissue kallikrein in uteroplacental units of the pregnant guinea-pig (Cavia porcellus).
Reprod Biol Endocrinol. 2007;527.
BACKGROUND: In humans trophoblast invasion and vascular remodeling are critical to determine the fate of pregnancy. Since guinea-pigs share with women an extensive migration of the trophoblasts through the decidua and uterine arteries, and a haemomonochorial placenta, this species was used to evaluate the spatio-temporal expression of three enzymes that have been associated to trophoblast invasion, MMP-2, MMP-9 and tissue kallikrein (K1). METHODS: Uteroplacental units were collected from early to term pregnancy. MMP-2, MMP-9 and K1 were analysed by immunohistochemistry and Western blot. The activities of MMP-2 and MMP-9 were assessed by gelatin zymography. RESULTS: Immunoreactive MMP-2, MMP-9 and K1 were detected in the subplacenta, interlobar and labyrinthine placenta, syncytial sprouts and syncytial streamers throughout pregnancy. In late pregnancy, perivascular or intramural trophoblasts expressed the three enzymes. The intensity of the signal in syncytial streamers was increased in mid and late pregnancy for MMP-2, decreased in late pregnancy for MMP-9, and remained stable for K1. Western blots of placental homogenates at days 20, 40 and 60 of pregnancy identified bands with the molecular weights of MMP-2, MMP-9 and K1. MMP-2 expression remained constant throughout gestation. In contrast, MMP-9 and K1 attained their highest expression during midgestation. Placental homogenates of 20, 40 and 60 days yielded bands of gelatinase activity that were compatible with MMP-2 and MMP-9 activities. ProMMP-2 and MMP-9 activities did not vary along pregnancy, while MMP-2 and MMP-9 increased at 40 and 40-60 days respectively. CONCLUSION: The spatio-temporal expression of MMPs and K1 supports a relevant role of these proteins in trophoblast invasion, vascular remodeling and placental angiogenesis, and suggests a functional association between K1 and MMP-9 activation. [Abstract/Link to Full Text]

da Silva VM, Carter AM, Ambrosio CE, Carvalho AF, Bonatelli M, Lima MC, Miglino MA
Placentation in dolphins from the Amazon River Basin: the Boto, Inia geoffrensis, and the Tucuxi, Sotalia fluviatilis.
Reprod Biol Endocrinol. 2007;526.
A recent reassessment of the phylogenetic affinities of cetaceans makes it timely to compare their placentation with that of the artiodactyls. We studied the placentae of two sympatric species of dolphin from the Amazon River Basin, representing two distinct families. The umbilical cord branched to supply a bilobed allantoic sac. Small blood vessels and smooth muscle bundles were found within the stroma of the cord. Foci of squamous metaplasia occurred in the allanto-amnion and allantochorion. The interhemal membrane of the placenta was of the epitheliochorial type. Two different types of trophoblastic epithelium were seen. Most was of the simple columnar type and indented by fetal capillaries. However, there were also areolar regions with tall columnar trophoblast and these were more sparsely supplied with capillaries. The endometrium was well vascularised and richly supplied with actively secreting glands. These findings are consistent with the current view that Cetacea are nested within Artiodactyla as sister group to the hippopotamids. [Abstract/Link to Full Text]

Harrison JL, Adam CL, Brown YA, Wallace JM, Aitken RP, Lea RG, Miller DW
An immunohistochemical study of the localization and developmental expression of ghrelin and its functional receptor in the ovine placenta.
Reprod Biol Endocrinol. 2007;525.
BACKGROUND: Ghrelin is an orexigenic hormone principally produced by the stomach, but also by numerous peripheral tissues including the placenta. Ghrelin acts via growth hormone secretagogue receptors (GHSR-1a) to alter food intake, fat utilization, and cellular proliferation, and has been suggested to play a role in the developmental growth of the fetoplacental unit. The placental expression of ghrelin and its role in ruminant species is not known. We tested the hypotheses that ghrelin and its functional receptor, GHSR-1a, are present in tissues of the ovine placenta, and that their expression is linked to the stage of development. METHODS: Antibodies raised against ghrelin and GHSR-1a were used in standard immunohistochemical protocols on placental tissues collected from pregnant ewes (n = 6 per gestational time point) at days 50, 80, 100, 128 and 135 of gestation (term approximately day 145). Immunostaining for ghrelin and GHSR-1a was quantified using computer-aided image analysis. Image analysis data were subjected to one-way ANOVA, with differences in immunostaining between time-points determined by Fisher's least significant difference. RESULTS: Positive immunostaining for ghrelin was detected in ovine placentae at all gestational time points, with staining localized to the maternal epithelium, caruncle and trophectoderm. There was a significant effect of gestational age (p < 0.001) on the placental expression of ghrelin, with maximal levels at gestational day 80. GHSR-1a immunostaining was detected in the fetal trophectoderm at all time points. In contrast to the gestational pattern of ghrelin expression, there was no effect of gestational age on placental GHSR-1a immunoexpression. CONCLUSION: Ghrelin and GHSR-1a are both present in the ovine placenta, and ghrelin displays a developmentally-related pattern of expression. Therefore, these data strongly suggest that the ghrelin system may have a role in feto-placental development in sheep. [Abstract/Link to Full Text]

Morales L, Ricardo B, Bolaños A, Chavira R, Domínguez R
Ipsilateral vagotomy to unilaterally ovariectomized pre-pubertal rats modifies compensatory ovarian responses.
Reprod Biol Endocrinol. 2007;524.
The present study evaluates the participation of the vagus nerve in pre-pubertal rats with unilateral ovariectomy on puberty onset, and on progesterone, testosterone and estradiol serum levels, and the compensatory responses of the ovary. Unilateral vagotomy did not modify the onset of puberty in unilaterally ovariectomized rats. Ovulation rates of animals with the left vagus nerve sectioned and the left ovary in-situ was lower than in rats with only unilateral ovariectomy. Sectioning the left vagus to 32-day old rats with the left ovary in-situ resulted in lower compensatory ovarian hypertrophy than in rats with right unilateral ovariectomy. Twenty-eight or 32-day old animals with sectioning of the right vagus nerve and the right ovary in situ showed higher compensatory ovulation. Twenty-eight -day old rats with the right ovary in situ had higher progesterone and testosterone levels than animals of the same age with the left ovary in-situ. Compared to animals with the right ovary in situ, animals treated at 32-days of age, sectioning the ipsi-lateral vagus nerve resulted in higher progesterone levels. Higher progesterone levels were observed in 28- and 32 days old rats with the left ovary in situ and left vagus nerve sectioned. Thirty-two day old animals with the right ovary in situ and right vagus nerve sectioned had higher progesterone levels than rats of the same age with the left ovary in situ and left vagus nerve sectioned. Left vagotomy to 28-day old rats with the left ovary in situ resulted in higher testosterone levels, a reverse response to that observed in animals with sectioning of the right vagus and the right ovary in situ. Thirty-two day old rats with the left ovary in situ and left vagus nerve sectioned showed lower testosterone levels than animals without vagotomy and with the left ovary in situ.Twenty-eight -day old animals with the left vagus sectioned and left ovary in situ had lower estradiol serum levels than rats without unilateral vagotomy, a response similar to that observed in 32-day old rats with the right ovary in situ and right vagus nerve sectioned.Present results suggest an asymmetric regulation of steroid hormones secretion by the vagus nerve innervations in animals with unilateral ovariectomy, and those differences in testosterone serum levels observed are associated to the ovary remaining in-situ, vagal innervation and age when the animals were treated. [Abstract/Link to Full Text]

Rago V, Aquila S, Panza R, Carpino A
Cytochrome P450arom, androgen and estrogen receptors in pig sperm.
Reprod Biol Endocrinol. 2007;523.
BACKGROUND: Androgens and estrogens are crucial for mammalian sperm differentiation but their role in biology of mature male gamete is not still defined. The expression of proteins involved in the biosynthesis and action of these steroid hormones has been demonstrated in human spermatozoa, but very few data have been reported in mature sperm from non human species. The purpose of the current study was to investigate the expression of aromatase (P450arom), estrogen (ERalpha/ERbeta) and androgen (AR) receptors in ejaculated spermatozoa of pig. METHODS: The immunfluorescence experiments were carried out treating pig sperm with anti-P450arom, anti-ERalpha, anti-ERbeta and anti-AR as primary antibodies, while Texas-Red/FITC conjugated IgG were applied as secondary antibodies. Furthermore, Western blot analysis was performed on sperm lysates. RESULTS: Aromatase was immunolocalized in the sperm tail, ERalpha and AR were localised in the sperm midpiece, while ERbeta was confined in the acrosomal region of the male gamete. Immunoblots detected a ~52 kDa aromatase band, a ~110 kDa AR band, a ~67 kDa ERalpha and two ERbeta bands, at ~50 kDa and ~59 kDa. CONCLUSION: This is the first report demonstrating that pig ejaculated spermatozoa express aromatase, estrogen and androgen receptors with a differential intra-cellular localization revealing a species-specific expression pattern. Therefore, pig sperm could be considered as a potential estrogen source while the different hormone cellular sites suggest distinct roles of androgens and estrogens in pig sperm physiology. [Abstract/Link to Full Text]

Croke JM, Pike LR, MacPhee DJ
The focal adhesion protein Hic-5 is highly expressed in the rat myometrium during late pregnancy and labour and co-localizes with FAK.
Reprod Biol Endocrinol. 2007;522.
BACKGROUND: Myometrial growth and remodeling of the cytoskeleton and focal adhesions during late pregnancy may be critical aspects of myometrial activation and thus labour. Yet our understanding of these aspects is inhibited by the paucity of information concerning the components of focal adhesions in the myometrium. The focal adhesion protein hydrogen peroxide-inducible clone-5 (Hic-5) has recently been found in mononuclear smooth muscle but was not examined in the myometrium during pregnancy. Thus, the goal of this study was to characterize Hic-5 mRNA and protein expression in the rat myometrium during pregnancy and labour. METHODS: Rat myometrium samples were obtained from non-pregnant animals, pregnant animals on days (d) 6, 12, 15, 17, 19, 21, 22, 23 (active labour) and 1 day postpartum (PP). In addition, myometrium samples were collected from rats within a progesterone-delayed labour paradigm. Hic-5 mRNA expression was analyzed by Northern blot analysis while Hic-5 protein expression was examined by immunoblot and immunofluorescence analysis. RESULTS: Hic-5 mRNA expression on d15, d19 and d21 was found to be significantly elevated compared to d6 and d12 of pregnancy and expression on d23 was significantly elevated over d6 (p < 0.05). Immunofluorescence analysis demonstrated that detection of Hic-5 protein in the circular muscle layer appeared to increase from d17 onwards, except PP, and Hic-5 was detectable in the cell cytoplasm and more continuously associated with myometrial cell membranes. In the longitudinal muscle layer Hic-5 was readily detectable by d15 and thereafter and primarily associated at myometrial cell membranes. Co-immunofluorescence analysis of potential Hic-5 and focal adhesion kinase (FAK) association in situ demonstrated a limited level of co-localization on d19, d23 and PP in the circular muscle layer while in the longitudinal muscle layer Hic-5 and FAK were readily co-localized at myometrial cell membranes. CONCLUSION: Hic-5 is highly expressed in the rat myometrium during late pregnancy and labour and co-localizes with FAK in situ. Our results are consistent with a potential role for Hic-5 in focal adhesion remodeling in the rat myometrium during late pregnancy. [Abstract/Link to Full Text]

Petrino TR, Toussaint G, Lin YW
Role of inhibin and activin in the modulation of gonadotropin- and steroid-induced oocyte maturation in the teleost Fundulus heteroclitus.
Reprod Biol Endocrinol. 2007;521.
BACKGROUND: Activin and inhibin are glycoproteins structurally related to the transforming growth factor-beta superfamily. These peptides were first described as factors that regulate the follicle-stimulating hormone (FSH) at the pituitary level. The possible role of inhibin and activin, at the ovarian level, in mediating the stimulatory actions of a Fundulus pituitary extract (FPE) and 17alpha,20beta-dihydroprogesterone (DHP) on oocyte maturation was investigated in this study. METHODS: In vitro culture of ovarian follicles and induction of oocyte maturation were carried out in 75% Leibovitz L-15 medium. Follicles or denuded oocytes were exposed to FPE, inhibin, activin, ethanol vehicle (control group), or DHP. The competence of the follicles or denuded oocytes to respond to the hormones was assessed by scoring germinal vesicle breakdown (GVBD) used as an indication of the reinitiation of meiosis or oocyte maturation. DHP level was measured by radioimmunoassay. RESULTS: Addition of FPE promoted the synthesis of DHP by the granulose cells of fully grown ovarian follicles and thus stimulated GVBD in the oocyte. Presence of porcine inhibin did not hinder the synthesis of DHP stimulated by FPE, although it did inhibit the subsequent GVBD in a dose-dependent manner, suggesting that the action of inhibin was at the oocyte level. Similarly to the findings with FPE, inhibin also blocked the DHP-induced GVBD in intact follicles, as well as the spontaneous and steroid-induced GVBD of denuded oocyte. Inhibin straightforwardly blocked the response to a low dose of DHP throughout the culture period, while higher doses of the steroid appeared to overcome the inhibitory effect especially at later times. In contrast to inhibin, recombinant human activin A significantly enhanced DHP-induced GVBD in a dose-dependent manner after 48 hr, although activin alone was not able to induce GVBD without the presence of the steroid. CONCLUSION: Taking together with our previous studies that demonstrate the presence of activin/inhibin subunits in the ovary of F. heteroclitus, these in vitro findings indicate that inhibin and activin are local regulators in the teleost ovary and have opposing effects in modulating oocyte maturation. [Abstract/Link to Full Text]

Liarte S, Chaves-Pozo E, García-Alcazar A, Mulero V, Meseguer J, García-Ayala A
Testicular involution prior to sex change in gilthead seabream is characterized by a decrease in DMRT1 gene expression and by massive leukocyte infiltration.
Reprod Biol Endocrinol. 2007;520.
BACKGROUND: Leukocytes are found within the testis of most, if not all, mammals and are involved in immunological surveillance, physiological regulation and tissue remodelling. The testis of seasonal breeding fish undergoes a regression process. In the present study, the second reproductive cycle (RC) of the protandrous seasonal teleost fish, gilthead seabream, was investigated and the presence of leukocytes analysed. Special attention has been paid to the testicular degenerative process which is particularly active in the last stage of the second RC probably due to the immediacy of the sex change process. METHODS: Sexually mature specimens (n = 10-18 fish/month) were sampled during the second RC. Some specimens were intraperitoneally injected with bromodeoxyuridin (BrdU) before sampling. Light and electron microscopy was used to determine the different stages of gonadal development and the presence of leukocytes and PCR was used to analyse the gene expression of a testis-differentiating gene and of specific markers for macrophages and B and T lymphocytes. Immunocytochemistry and flow cytometry were performed using a specific antibody against acidophilic granulocytes from the gilthead seabream. Cell proliferation was detected by immunocytochemistry using an anti-BrdU antibody and apoptotic cells by in situ detection of DNA fragmentation. RESULTS: The fish in the western Mediterranean area developed as males during the first two RCs. The testis of all the specimens during the second RC underwent a degenerative process, which started at post-spawning and was enhanced during the testicular involution stage, when vitellogenic oocytes appeared in the ovary accompanied by a progressive increase in the ovarian index. However, only 40% of specimens were females in the third RC. Leukocytes (acidophilic granulocytes, macrophages and lymphocytes) were present in the gonad and acidophilic granulocyte infiltration occurred during the last two stages. At the same time DMRT1 gene expression decreased. CONCLUSIONS: The results demonstrate that innate and adaptive immune cells are present in the gonads of gilthead seabream. Moreover, the whole fish population underwent a testicular degenerative process prior to sex change, characterized by high rates of apoptosis and necrosis and accompanied by an infiltration of acidophilic granulocytes and a decrease in DMRT1 levels. [Abstract/Link to Full Text]

Martins RS, Deloffre LA, Mylonas CC, Power DM, Canário AV
Developmental expression of DAX1 in the European sea bass, Dicentrarchus labrax: lack of evidence for sexual dimorphism during sex differentiation.
Reprod Biol Endocrinol. 2007;519.
BACKGROUND: DAX1 (NR0B1), a member of the nuclear receptors super family, has been shown to be involved in the genetic sex determination and in gonadal differentiation in several vertebrate species. In the aquaculture fish European sea bass, Dicentrarchus labrax, and in the generality of fish species, the mechanisms of sex determination and differentiation have not been elucidated. The present study aimed at characterizing the European DAX1 gene and its developmental expression at the mRNA level. METHODS: A full length European sea bass DAX1 cDNA (sbDAX1) was isolated by screening a testis cDNA library. The structure of the DAX1 gene was determined by PCR and Southern blot. Multisequence alignments and phylogenetic analysis were used to compare the translated sbDAX1 product to that of other vertebrates. sbDAX1 expression was analysed by Northern blot and relative RT-PCR in adult tissues. Developmental expression of mRNA levels was analysed in groups of larvae grown either at 15 degrees C or 20 degrees C (masculinising temperature) during the first 60 days, or two groups of fish selected for fast (mostly females) and slow growth. RESULTS: The sbDAX1 is expressed as a single transcript in testis and ovary encoding a predicted protein of 301 amino acids. A polyglutamine stretch of variable length in different DAX1 proteins is present in the DNA binding domain. The sbDAX1 gene is composed of two exons, separated by a single 283 bp intron with conserved splice sites in same region of the ligand binding domain as other DAX1 genes. sbDAX1 mRNA is not restricted to the brain-pituitary-gonadal axis and is also detected in the gut, heart, gills, muscle and kidney. sbDAX1 mRNA was detected as early as 4 days post hatching (dph) and expression was not affected by incubation temperature. Throughout gonadal sex differentiation (60-300 dph) no dimorphic pattern of expression was observed. CONCLUSION: The sbDAX1 gene and putative protein coding region is highly conserved and has a wide pattern of tissue expression. Although gene expression data suggests sbDAX1 to be important for the development and differentiation of the gonads, it is apparently not sex specific. [Abstract/Link to Full Text]

Chand AL, Murray AS, Jones RL, Hannan NJ, Salamonsen LA, Rombauts L
Laser capture microdissection and cDNA array analysis of endometrium identify CCL16 and CCL21 as epithelial-derived inflammatory mediators associated with endometriosis.
Reprod Biol Endocrinol. 2007;518.
BACKGROUND: Understanding the pathophysiology of chemokine secretion in endometriosis may offer a novel area of therapeutic intervention. This study aimed to identify chemokines differentially expressed in epithelial glands in eutopic endometrium from normal women and those with endometriosis, and to establish the expression profiles of key chemokines in endometriotic lesions. METHODS: Laser capture microdissection isolated epithelial glands from endometrial eutopic tissue from women with and without endometriosis in the mid-secretory phase of their menstrual cycles. Gene profiling of the excised glands used a human chemokine and receptor cDNA array. Selected chemokines were further examined using real-time PCR and immunohistochemistry. RESULTS: 22 chemokine/receptor genes were upregulated and two downregulated in pooled endometrial epithelium of women with endometriosis compared with controls. CCL16 and CCL21 mRNA was confirmed as elevated in some women with endometriosis compared to controls on individual samples. Immunoreactive CCL16 and CCL21 were predominantly confined to glands in eutopic and ectopic endometrium: leukocytes also stained. Immunoreactive CCL16 was overall higher in glands in ectopic vs. eutopic endometrium from the same woman (P < 0.05). Staining for CCL16 and CCL21 was highly correlated in individual tissues. CONCLUSION: This study provides novel candidate molecules and suggests a potential local role for CCL16 and CCL21 as mediators contributing to the inflammatory events associated with endometriosis. [Abstract/Link to Full Text]

Ushizawa K, Takahashi T, Hosoe M, Ishiwata H, Kaneyama K, Kizaki K, Hashizume K
Global gene expression analysis and regulation of the principal genes expressed in bovine placenta in relation to the transcription factor AP-2 family.
Reprod Biol Endocrinol. 2007;517.
BACKGROUND: Cell-cell communication is an important factor in feto-maternal units during placentogenesis. The placenta produces pivotal hormones and cytokines for communication between cotyledonary villi and the maternal caruncle. Gene expression in bovine placenta throughout pregnancy was comprehensively screened by a cDNA microarray, and we searched for a common transcription factor in a gene cluster that showed increasing expression throughout gestation in cotyledonary villi and caruncle. METHODS: Placentomal tissues (villi and caruncle) were collected from Day 25 to Day 250 of gestation for microarray analysis. Global gene expression profiles were analyzed using the k-means clustering method. A consensus sequence cis-element that may control up-regulated genes in a characteristic cluster was examined in silico. The quantitative expression and localization of a specific transcription factor were investigated in each tissue using quantitative real-time RT-PCR and in situ hybridization. RESULTS: The microarray expression profiles were classified into ten clusters. The genes with most markedly increased expression became concentrated in cluster 2 as gestation proceeded. Cluster 2 included placental lactogen (CSH1), pregnancy-associated glycoprotein-1 (PAG1), and sulfotransferase family 1E estrogen-preferring member 1 (SULT1E1), which were mainly detected in giant trophoblast binucleate cells (BNC). Consensus sequence analysis identified transcription factor AP-2 binding sites in some genes in this cluster. Quantitative real-time RT-PCR analysis confirmed that high level expression of transcription factor AP-2 alpha (TFAP2A) was common to cluster 2 genes during gestation. In contrast, the expression level of another AP-2 family gene, transcription factor AP-2 beta (TFAP2B), was extremely low over the same period. Another gene of the family, transcription factor AP-2 gamma (TFAP2C), was expressed at medium level compared with TFAP2A and TFAP2B. In situ hybridization showed that TFAP2A, TFAP2B and TFAP2C mRNAs were localized in trophoblast cells but were expressed by different cells. TFAP2A was expressed in cotyledonary epithelial cells including BNC, TFAP2B was specifically expressed in BNC, and TFAP2C in mononucleate cells. CONCLUSION: We detected gestational-stage-specific gene expression profiles in bovine placentomes using a combination of microarray and in silico analysis. In silico analysis indicated that the AP-2 family may be a consensus regulator for the gene cluster that characteristically appears in bovine placenta as gestation progresses. In particular, TFAP2A and TFAP2B may be involved in regulating binucleate cell-specific genes such as CSH1, some PAG or SULT1E1. These results suggest that the AP-2 family is a specific transcription factor for clusters of crucial placental genes. This is the first evidence that TFAP2A may regulate the differentiation and specific functions of BNC in bovine placenta. [Abstract/Link to Full Text]

Tithof PK, Roberts MP, Guan W, Elgayyar M, Godkin JD
Distinct phospholipase A2 enzymes regulate prostaglandin E2 and F2alpha production by bovine endometrial epithelial cells.
Reprod Biol Endocrinol. 2007;516.
BACKGROUND: The rate-limiting step in prostaglandin (PG) biosynthesis is catalyzed by phospholipase A2 (PLA2) enzymes which hydrolyze arachidonic acid from membrane phospholipids. Despite their importance in uterine PG production, little is known concerning the specific PLA2 enzymes that regulate arachidonic acid liberation in the uterine endometrium. The objectives of this study were to evaluate the expression and activities of calcium-independent Group VI and Group IVC PLA2 (PLA2G6 and PLA2G4C) and calcium-dependent Group IVA PLA2 (PLA2G4A) enzymes in the regulation of bovine uterine endometrial epithelial cell PG production. METHODS: Bovine endometrial epithelial cells in culture were treated with oxytocin, interferon-tau and the PLA2G6 inhibitor bromoenol lactone, alone and in combination. Concentrations of PGF2alpha and PGE2 released into the medium were analyzed. Western blot analysis was performed on cellular protein to determine the effects of treatments on expression of PLA2G4A, PLA2G6 and PLA2G4C. Group-specific PLA2 activity assays were performed on cell lysates following treatment with oxytocin, interferon-tau or vehicle (control), alone and in combination. To further evaluate the role of specific PLA2 enzymes in uterine cell PG biosynthesis, cells were transfected with cDNAs encoding human PLA2G6 and PLA24C, treated as described above and PG assays performed. RESULTS: Constitutive cell production of PGF2alpha was about two-fold higher than PGE2. Oxytocin stimulated production of both PGs but the increase of PGF2alpha was significantly greater. Interferon-tau diminished oxytocin stimulation of both PGs. The PLA2G6 inhibitor, bromoenol lactone, abolished oxytocin-stimulated production of PGF2alpha. Treatments had little effect on PLA2G4A protein expression. In contrast, oxytocin enhanced expression of PLA2G6 and this effect was diminished in the presence of interferon-tau. Expression of PLA2G4C was barely detectable in control and oxytocin treated cells but it was enhanced in cells treated with interferon-tau. Oxytocin stimulated PLA2 activity in assays designed to evaluate PLA2G6 activity and interferon-tau inhibited this response. In assays designed to measure PLA2G4C activity, only interferon-tau was stimulatory. Cells overexpressing PLA2G6 produced similar quantities of the two PGs and these values were significantly higher than PG production by non-transfected cells. Oxytocin stimulated production of both PGs and this response was inhibited by interferon-tau. Bromoenol lactone inhibited oxtocin stimulation of PGF2alpha production but stimulated PGE2 production, both in the absence and presence of oxytocin. Cells over-expressing PLA2G4C produced more PGE2 than PGF2alpha and interferon-tau stimulated PGE2 production. CONCLUSION: Results from these studies indicate that oxytocin stimulation of uterine PGF2alpha production is mediated, at least in part, by up-regulation of PLA2G6 expression and activity. In addition to its known inhibitory effect on oxytocin receptor expression, interferon-tau represses oxytocin-stimulated PLA2G6 expression and activity and this contributes to diminished PGF2alpha production. Furthermore, endometrial cell PGE2 biosynthesis was associated with PLA2G4C expression and activity and interferon-tau was stimulatory to this process. [Abstract/Link to Full Text]