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Recent Articles in Endocrinology

Salani B, Briatore L, Garibaldi S, Cordera R, Maggi D
Caveolin-1 down regulation inhibits IGF-IR signal transduction in H9C2 rat cardio myoblasts.
Endocrinology. 2007 Nov 26; .
Caveolin-1, the major caveolar protein, directly interacts with IGF-I Receptor (IGF-IR) and its intracellular substrates. To determine the role of caveolin-1 in IGF-IR signaling, we transfected H9C2 cells with small interfering RNA specific for caveolin-1 (Cav-1-siRNA). The selective down regulation of caveolin-1 (90%) was associated with a smaller reduction of caveolin-2 while caveolin-3 expression was unaffected. A significant reduction of IGF-IR tyrosine phosphorylation in Cav-1-siRNA H9C2 cells was found compared to H9C2 control cells (Ctr-siRNA). The reduced IGF-IR auto phosphorylation resulted in a decrease of IRS-1, Shc and Akt activation. In addition, in Cav-1-siRNA H9C2 cells IGF-I did not prevented apoptosis, suggesting that caveolin-1 is required to mediate the anti-apoptotic effect of IGF-I in cardio myoblasts. The down regulation of caveolin-1 decreased IGF-IR activation and affected the ability of IGF-I to prevent apoptosis after serum withdrawal also in human umbilical vein endothelial cells (HUVECs). These results demonstrate that: 1) caveolin-1 down regulation negatively affects IGF-IR tyrosine phosphorylation; 2) this effect causes a reduced activation of IRS-1, Shc, Akt; 3) caveolin-1 is involved in IGF-IR antiapoptotic signaling following serum deprivation. [Abstract/Link to Full Text]

Kagawa S, Soeda Y, Ishihara H, Oya T, Sasahara M, Yaguchi S, Oshita R, Wada T, Tsuneki H, Sasaoka T
Impact of Transgenic Overexpression of SH2-Containing Inositol 5'-Phosphatase 2 on Glucose Metabolism and Insulin Signaling in Mice.
Endocrinology. 2007 Nov 26;
SHIP2 is a 5'-lipid phosphatase hydrolyzing the PI3-kinase product PI(3,4,5)P3 to PI(3,4)P2 in the regulation of insulin signaling, and is shown to be increased in peripheral tissues of diabetic db/db mice. To clarify the impact of SHIP2 in the pathogenesis of insulin resistance with type 2 diabetes, we generated transgenic mice overexpressing SHIP2. The body weight of transgenic mice increased by 5.0% (p<0.05) compared to control wild-type littermates on a normal chow diet, but not on a high-fat diet. Glucose tolerance and insulin sensitivity were mildly but significantly impaired in the transgenic mice only when maintained on the normal chow diet, as shown by 1.2-fold increase in glucose area under the curve over control levels at 9 months old. Insulin-induced phosphorylation of Akt was decreased in the SHIP2-overexpressing fat, skeletal muscle, and liver. In addition, the expression of hepatic mRNAs for glucose-6-phosphatase and phosphoenolpyruvate carboxykinase was increased, that for sterol regulatory element-binding protein 1 was unchanged, and that for glucokinase was decreased. Consistently, hepatic glycogen content was reduced in the 9-month-old transgenic mice. Structure and insulin content were histologically normal in the pancreatic islets of transgenic mice. These results indicate that increased abundance of SHIP2 in vivo contributes, at least in part, to the impairment of glucose metabolism and insulin sensitivity on a normal chow diet, possibly by attenuating peripheral insulin signaling and by altering hepatic gene expression for glucose homeostasis. [Abstract/Link to Full Text]

Gaide Chevronnay HP, Cornet PB, Delvaux D, Lemoine P, Courtoy PJ, Henriet P, Marbaix E
OPPOSITE REGULATION OF TRANSFORMING GROWTH FACTORS-BETA 2 AND -BETA 3 EXPRESSION IN THE HUMAN ENDOMETRIUM.
Endocrinology. 2007 Nov 26;
Transforming growth factors-beta (TGF-betas) have been reported to mediate the repression by progesterone of several matrix metalloproteinases in the human endometrium, thereby preventing menstrual breakdown. Because of conflicting reports on the expression profiles, source and regulation of the TGF-beta system in this tissue, we investigated by real-time RT-PCR and ELISA the expression of the three TGF-betas (total and mature forms) and their two receptors throughout the menstrual cycle, and their regulation by ovarian steroids in cultured explants including in their microdissected epithelial and stromal compartments. Regulation by cAMP and MAPK was further investigated. This comprehensive study on a large collection of endometrial samples evidenced a differential regulation of TGF-beta isoforms expression, both in vivo and in explant culture. In vivo, TGF-beta2 increased by about 5-fold at the mid-late secretory phase then declined after menstruation; TGF-beta3 increased at menstruation and remained high during the proliferative phase; TGF-beta1 was maximal at menstruation. In explants cultured, without ovarian steroids both TGF-beta2 and -beta3 were preferentially expressed in the stroma. Ovarian steroids strongly repressed both TGF-beta2 and -beta3 in stroma but only TGF-beta2 in glands. cAMP prevented inhibition by ovarian steroids of TGF-beta2 but not of -beta3. In presence of ovarian steroids, MAPK inhibitors (p38 and ERK pathways) stimulated TGF-beta3 but inhibited TGF-beta2 expression. In conclusion, TGF-beta2 and -beta3 are differentially expressed during the menstrual cycle and regulated by progesterone in epithelial vs stromal cells. The opposite regulation of TGF-beta2 and -beta3 by cAMP and MAPK could account for their distinct expression in vivo. [Abstract/Link to Full Text]

Choi DC, Evanson NK, Furay AR, Ulrich-Lai YM, Ostrander MM, Herman JP
The anteroventral bed nucleus of the stria terminalis differentially regulates HPA axis responses to acute and chronic stress.
Endocrinology. 2007 Nov 26;
The anteroventral region of the bed nucleus of the stria terminalis (BST) stimulates hypothalamic-pituitary-adrenocortical (HPA) axis responses to acute stress. However, the role of the anterior BST nuclei in chronic drive of the HPA axis has yet to be established. Therefore, this study tests the role of the anteroventral BST in physiological responses to chronic drive, using a chronic variable stress (CVS) model. Male Sprague-Dawley rats received either bilateral ibotenate lesions, targeting the anteroventral BST, or vehicle injection into the same region. Half of the lesion and control rats were exposed 14 day CVS paradigm consisting of twice daily exposure to unpredictable, alternating stressors. The remaining rats were non-handled control animals that remained in home cages. On the morning after the end of CVS exposure, all rats were exposed to a novel restraint stress challenge. CVS induced attenuated body weight gain, adrenal hypertrophy, thymic involution, and enhanced CRH mRNA in hypophysiotrophic neurons of the hypothalamic paraventricular nucleus (PVN), none of which were affected by anteroventral BST lesions. In the absence of CVS, lesions attenuated the plasma corticosterone and PVN c-fos mRNA responses to the acute restraint stress. In contrast, lesions of the anteroventral BST elevated plasma ACTH and corticosterone responses to novel restraint in the rats previously exposed to CVS. These data suggest that the anterior BST plays very different roles in integrating acute stimulation and chronic drive of the HPA axis, perhaps mediated by chronic stress-induced recruitment of distinct BST cell groups or functional reorganization of stress-integrative circuits. [Abstract/Link to Full Text]

Pan W, Hsuchou H, Tu H, Kastin AJ
Developmental changes of leptin receptors in cerebral microvessels: unexpected relation to leptin transport.
Endocrinology. 2007 Nov 26;
The adipokine leptin participates not only in the regulation of feeding and obesity in adults, but also in neonatal development. It crosses the blood-brain barrier (BBB) by receptor-mediated transport. Leptin concentrations in blood differ between neonates and adults. We determined the developmental changes of leptin receptor subtypes in the cerebral microvessels composing the BBB and examined their expected correlation with leptin transport across the BBB. Total RNA was extracted from enriched cerebral microvessels of mice 1, 7, 14, and 60 days of age for real-time RT-PCR analysis of leptin receptor subtypes. In cerebral microvessels from neonates, ObRa, ObRb, ObRc, and ObRe mRNA were all higher than in adults, but ObRd was not detectable. Hypothalamus showed similar age-related changes except for ObRb, which was higher in adults. The homologous receptor gp130 did not show significant age-related changes in either region. Despite the increase of leptin receptors, leptin permeation across the BBB after intravenous injection was less in the neonates. In-situ brain perfusion with blood-free buffer showed no significant difference in the brain uptake of leptin between neonates and adults, indicating an antagonistic role of leptin binding proteins in the circulation, especially the soluble receptor ObRe. The results are consistent with our previous finding that ObRe antagonizes leptin endocytosis in cultured endothelia and transport from blood to brain in mice. Overall, the developmental changes observed for leptin receptors unexpectedly failed to correlate with the entry of leptin into brain, and this may indicate different functions of the receptors in neonates and adults. [Abstract/Link to Full Text]

Wade JM, Juneja P, Mackay AW, Graham J, Havel PJ, Tecott LH, Goulding EH
Synergistic impairment of glucose homeostasis in ob/ob mice lacking functional serotonin 2C receptors.
Endocrinology. 2007 Nov 26;
To investigate how serotonin and leptin interact in the regulation of energy balance and glucose homeostasis, we generated a genetic mouse model, the OB2C mouse, which lacks functional serotonin 2C receptors (5HT2CRs) and the adipocyte hormone leptin. The OB2C mice exhibited a dramatic diabetes phenotype, evidenced by a synergistic increase in serum glucose levels and water intake. The severity of the animals' diabetes phenotype would not have been predicted from the phenotypic characterization of mice bearing mutations of either the leptin (OB mutant mice) or the 5HT2CR gene (2C mutant mice). The synergistic impairment in glucose homeostasis developed at an age when OB2C mice did not differ in body weight from OB mice, suggesting that this impairment was not an indirect consequence of increased adiposity. We also demonstrated that the improvement in glucose tolerance in wild-type mice treated with the serotonin releaser and reuptake inhibitor fenfluramine was blunted in 2C mutant mice. These pharmacological and genetic findings provide evidence that the serotonin 2C receptor has direct effects on glucose homeostasis. [Abstract/Link to Full Text]

Iosef C, Gkourasas T, Jia CY, Li SS, Han VK
A Functional Nuclear Localization Signal in Insulin-like Growth Factor Binding Protein-6 Mediates its Nuclear Import.
Endocrinology. 2007 Nov 26;
IGFBP-6 is a member of the insulin-like growth factor binding protein (IGFBP) family that regulates the actions of IGFs. Although IGFBPs exert their functions extracellularly in an autocrine/paracrine manner, several members of the family, such as IGFBP-3 and -5, possess nuclear localization signals (NLS). To date, no NLS has been described for IGFBP-6, an IGFBP that binds preferentially to IGF-II. We report here that both exogenous and endogenous IGFBP-6 could be imported into the nuclei of rhabdomyosarcoma (RD) and HEK-293 cells. Nuclear import of IGFBP-6 was mediated by a NLS sequence that bears limited homology to those found in IGFBP-3 and -5. IGFBP-6 nuclear translocation was an active process that required importins. A peptide corresponding to the IGFBP-6 NLS bound preferentially to importin-alpha. A comprehensive peptide array study revealed that, in addition to positively charged residues such as Arg and Lys, amino acids notably Gly and Pro within the NLS, played an important part in binding to importins. Overexpression of wild type IGFBP-6 increased apoptosis, and the addition of IGF-II did not negate this effect. Only the deletion of the NLS segment abolished the apoptosis effect. Taken together, these results suggest that IGFBP-6 is translocated to the nucleus with functional consequences, and that different members of the IGFBP family have specific nuclear import mechanisms. [Abstract/Link to Full Text]

Wilson-O'Brien AL, Dehaan CL, Rogers S
Mitogen stimulated and rapamycin sensitive GLUT12 targeting and functional glucose transport in renal epithelial cells.
Endocrinology. 2007 Nov 26;
We hypothesized that GLUT12 is involved in regulation of glucose flux in distal renal tubules in response to elevated glucose. We used the MDCK polarized epithelial cell model and neutralizing antibodies to analyze GLUT12 targeting and directional GLUT12 mediated glucose transport. At physiological glucose concentrations, GLUT12 was localized to a perinuclear position. High glucose and serum treatment resulted in GLUT12 localization to the apical membrane. This mitogen stimulated targeting of GLUT12 was inhibited by rapamycin, the specific inhibitor of mTOR. The functional role of GLUT12 was also examined. We constructed a GLUT12 cDNA containing a c-Myc epitope tag in the fifth exofacial loop. Assays of glucose transport at the apical membrane were performed using Transwell filters. By comparing transport assays in the presence of neutralizing anti-c-Myc monoclonal antibody we specifically measured GLUT12 mediated glucose transport at the apical surface. GLUT12 mediated glucose transport was mitogen dependent and rapamycin sensitive. Our results implicate mTOR signaling in a novel pathway of glucose transporter protein targeting and glucose transport. Activity of the mTOR pathway has been associated with diabetic kidney disease. Our results provide evidence for a link between GLUT12 protein trafficking, glucose transport and signaling molecules central to the control of metabolic disease processes. [Abstract/Link to Full Text]

Richter HG, Torres-Farfan C, Garcia-Sesnich J, Abarzua-Catalan L, Henriquez MG, Alvarez-Felmer M, Gaete F, Rehren GE, Seron-Ferre M
Rhythmic expression of functional MT1 melatonin receptors in the rat adrenal gland.
Endocrinology. 2007 Nov 26;
We previously demonstrated that melatonin is involved in the regulation of adrenal glucocorticoid production in diurnal primates, through activation of MT1 membrane-bound melatonin receptors. However, whether melatonin has a similar role in nocturnal rodents remains unclear. Using an integrative approach, here we show that the adult rat adrenal gland expresses a functional MT1 melatonin receptor in a rhythmic fashion. We found: (1) expression of the cognate mRNA encoding for the MT1 membrane-bound melatonin receptor, displaying higher levels in the day/night transition (1800-2200 h); (2) expression of the predicted 37 kDa MT1 polypeptide in immunoblots from adrenals collected at 2200 h but not 1000 h; (3) no expression of the MT2 melatonin receptor mRNA and protein; (4) specific high affinity 2-[(125)I]iodomelatonin binding in membrane fractions and frozen sections from adrenals collected at 2200 h but not 0800 h (dissociation constant = 14.22 +/- 1.23 pM; maximal binding capacity = 0.88 +/- 0.02 fmol/mg protein); and (5) in vitro clock time-dependent inhibition of ACTH-stimulated corticosterone production by 1-100 nM melatonin, which was reversed by 1 microM luzindole (a melatonin membrane receptor antagonist). Our findings indicate not only expression, but also high amplitude diurnal variation of functional MT1 melatonin receptors in the rat adrenal gland. It is conceivable that plasma melatonin may play a role to fine tune corticosterone production in nocturnal rodents; probably contributing to the down slope of the corticosterone rhythm. [Abstract/Link to Full Text]

Deboer MD, Zhu X, Levasseur PR, Inui A, Hu Z, Han G, Mitch WE, Taylor JE, Halem HA, Dong JZ, Datta R, Culler MD, Marks DL
Ghrelin Treatment of Chronic Kidney Disease: Improvements in Lean Body Mass and Cytokine Profile.
Endocrinology. 2007 Nov 26;
Chronic kidney disease (CKD) is associated with an increase in inflammatory cytokines and can result in cachexia with loss of muscle and fat stores. We previously demonstrated efficacy of treating a model of cancer cachexia with ghrelin and a ghrelin receptor agonist. Currently, we examine a surgical model of CKD in rats, resulting in uremia and decreased accrual of lean body mass. Treatment with ghrelin and two ghrelin receptor agonists (BIM-28125 and BIM-28131) resulted in increased food intake and an improvement in lean body mass accrual that was related in part to a decrease in muscle protein degradation as assessed by muscle levels of the 14 kD actin fragment resulting from cleaved actomyosin. Additionally there was a decrease in circulating inflammatory cytokines in nephrectomized animals treated with ghrelin relative to saline treatment. Ghrelin-treated animals also had a decrease in the expression of IL-1 receptor in the brainstem and a decrease in expression of pro-hormone convertase-2 (PC-2), an enzyme involved in the processing of pro-opiomelanocortin (POMC) to the anorexigenic peptide alpha-MSH. We conclude that ghrelin treatment in uremia results in improved lean mass accrual in part due to suppressed muscle proteolysis and possibly related to anti-inflammatory effects. [Abstract/Link to Full Text]

Parent AS, Rasier G, Matagne V, Lomniczi A, Lebrethon MC, G�rard A, Ojeda S, Bourguignon JP
OXYTOCIN FACILITATES FEMALE SEXUAL MATURATION THROUGH A GLIA-TO-NEURON SIGNALING PATHWAY.
Endocrinology. 2007 Nov 26;
It has been earlier proposed that oxytocin could play a facilitatory role in the preovulatory luteinizing hormone (LH) surge both in rats and humans. We here provide evidence that oxytocin also facilitates sexual maturation in female rats. The administration of an oxytocin antagonist for six days to immature female rats decreased gonadotropin-releasing hormone (GnRH) pulse frequency ex vivo, and delayed the age at vaginal opening and first estrus. The in vitro reduction in GnRH pulse frequency required chronic blockade of oxytocin receptors, as it was not acutely observed after a single injection of the antagonist. Hypothalamic explants exposed to the antagonist in vitro, showed a reduced GnRH pulse frequency and failed to respond to oxytocin with GnRH release. Prostaglandin E2 (PGE2) mimicked the stimulatory effect of oxytocin on GnRH pulse frequency, and inhibition of PG synthesis blocked the effect of oxytocin, suggesting that oxytocin accelerates pulsatile GnRH release via PGE2. The source of PGE2 appears to be astrocytes, because oxytocin stimulates PGE2 release from cultured hypothalamic astrocytes. Moreover, astrocytes express oxytocin receptors whereas GnRH neurons do not. These results suggest that oxytocin facilitates female sexual development, and that this effect is mediated by a mechanism involving glial production of PGE2. [Abstract/Link to Full Text]

Pawson AJ, Faccenda E, Maudsley S, Lu ZL, Naor Z, Millar RP
Mammalian Type I GnRH Receptors Undergo Slow, Constitutive, Agonist-Independent Internalization.
Endocrinology. 2007 Nov 26;
Regulatory elements present in the cytoplasmic carboxyl-terminal tails of GPCRs contribute to agonist-dependent receptor desensitization, internalization, and association with accessory proteins such as beta-arrestin. The mammalian type I GnRH receptors are unique among the rhodopsin-like GPCRs because they lack a cytoplasmic carboxyl-terminal tail. In addition, they do not recruit beta-arrestin, nor do they undergo rapid desensitization. By measuring the internalization of labeled GnRH agonists, previous studies have reported that mammalian type I GnRH receptors undergo slow agonist-dependent internalization. In the present study, we have measured the internalization of epitope-tagged GnRH receptors, both in the absence and presence of GnRH stimulation. We demonstrate that mammalian type I GnRH receptors exhibit a low level of constitutive agonist-independent internalization. Stimulation with GnRH agonist did not significantly enhance the level of receptor internalization above the constitutive level. In contrast, the catfish GnRH and rat TRH receptors which have cytoplasmic carboxyl-terminal tails, displayed similar levels of constitutive agonist-independent internalization, but underwent robust agonist-dependent internalization, as did chimeras of the mammalian type I GnRH receptor with the cytoplasmic carboxyl-terminal tails of the catfish GnRH receptor or the rat TRH receptor. When the carboxyl-terminal Tyr325 and Leu328 residues of the mammalian type I GnRH receptor were replaced with Alanines, these two mutant receptors underwent significantly impaired internalization, suggesting a function for the Tyr-X-X-Leu sequence in mediating the constitutive agonist-independent internalization of mammalian type I GnRH receptors. These findings provide further support for the underlying notion that the absence of the cytoplasmic carboxyl-terminal tail of the mammalian type I GnRH receptors has been selected for during evolution, to prevent rapid receptor desensitization and internalization, in order to allow protracted GnRH signaling in mammals. [Abstract/Link to Full Text]

Banu SK, Lee J, Speights VO, Starzinski-Powitz A, Arosh JA
CYCLOOXYGENASE-2 REGULATES SURVIVAL, MIGRATION AND INVASION OF HUMAN ENDOMETRIOTIC CELLS THROUGH MULTIPLE MECHANISMS.
Endocrinology. 2007 Nov 26;
Endometriosis is a debilitating disease characterized by the presence of functional endometrial glandular epithelium and stroma outside the uterine cavity that affects up to 20% of women of child-bearing age. Cyclooxygenase-2 (COX-2), a rate limiting enzyme in the biosynthesis of prostaglandin (PGE2), is highly expressed in endometriotic tissues and results in increased concentrations of peritoneal PGE2 in women. In this study, we determined the expression of COX-2 protein in ectopic and eutopic endometria in human; and the role of COX-2 in endometriotic cell survival, migration and invasion in human. Our results indicate that COX-2 protein is abundantly expressed in ectopic endometria compared with eutopic endometria. Comparatively, expression of COX-2 protein is higher in eutopic endometria from women with endometriosis compared to women without endometriosis. Inhibition of COX-2 decreases survival, migration and invasion of endometriotic cells which are associated with decreased production of PGE2. Cell growth inhibitory effects of COX-2 inhibition/silencing are mediated through nuclear poly (ADP-ribose) polymerase (PARP)-mediated apoptosis. Cell motility and invasion inhibitory effects of COX-2 inhibition/silencing are mediated through metalloproteinases MMP2 and MMP9 activities. Interestingly, effects of COX-2 inhibition is more profound in endometriotic epithelial than in stromal cells. Further, inhibition of COX-2 affects invasion rather than migration of endometriotic epithelial and stromal cells. It is the first evidence showing that inhibition of COX-2 decreases endometriotic epithelial and stromal cells survival, migration and invasion in human. Our results support the emerging concept that COX-2/PGE2 promotes the pathophysiology and pathogenesis of endometriosis in human. [Abstract/Link to Full Text]

Wyman A, Pinto A, Sheridan R, Moley KH
One-cell zygote transfer from diabetic to non-diabetic mouse results in congenital malformations and growth retardation in offspring.
Endocrinology. 2007 Nov 26;
Fetuses of type 1 and type 2 diabetic women experience higher incidences of malformations and fetal death as compared to non diabetics even when they achieve adequate glycemic control during the first trimester. We hypothesize that maternal diabetes adversely affects the earliest embryonic stage post fertilization and programs the fetus to experience these complications. To test this hypothesis we transferred either one-cell mouse zygotes or blastocysts from either streptozotocin-induced diabetic or control mice into non-diabetic pseudopregnant female recipients. We then evaluated the fetuses at embryonic day 14.5 in order to assess fetal growth and the presence or absence of malformations. We found that fetuses from the diabetic mice transferred at the blastocyst stage but also as early as the one-cell zygote stage displayed significantly higher rates of malformations consistent with neural tube closure problems and abdominal wall and limb deformities. In addition, both these groups of fetuses were significantly growth retarded. In order to determine if this phenomenon was due to high glucose concentrations, two-cell embryos were cultured to a blastocyst stage in 52mM D-glucose or L-glucose as an osmotic control, transferred into non-diabetic pseudopregnant mice, and examined at embryonic day 14.5. These embryos did not demonstrate any evidence of malformations, how ever did experience significantly higher rates of resorptions, lower implantation rates and they were significantly smaller at e14.5. In summary, exposure to maternal diabetes during oogenesis, fertilization and the first 24 hours was enough to program permanently the fetus to develop significant morphologic changes. [Abstract/Link to Full Text]

Tse PK, Lee YL, Chow WN, Luk JM, Lee KF, Yeung WS
PREIMPLANTATION EMBRYOS CO-OPERATES WITH OVIDUCTAL CELLS TO PRODUCE EMBRYOTROPHIC IC3B.
Endocrinology. 2007 Nov 26;
Human oviductal epithelial (OE) cells produce complement protein-3 (C3) and its derivatives C3b and iC3b. Among them, iC3b is the most potent embryotrophic molecule. We studied the production of iC3b in the oviductal cell/embryo culture system. In the immune system, C3 convertase converts C3 into C3b, and the conversion of C3b to iC3b requires factor-I and its cofactors, such as factor-H or membrane cofactor protein (MCP). Human oviductal epithelium and OE cells expressed mRNA and protein of the components of C3 convertase, including C2, C4, factor-B and factor-D. The OE cell conditioned medium contained active C3 convertase activity that was suppressed by C3 convertase inhibitor, H17 in a dose and time dependent manner. While the oviductal epithelium and OE cells produced factor-I, the production of its cofactor, factor-H required for the conversion of C3b to iC3b, was weak. Thus OE cells conditioned medium was inefficient in producing iC3b from exogenous C3b. On the contrary, mouse embryos facilitated such conversion to iC3b, which was taken up by the embryos resulting in the formation of more blastocysts of larger size. The facilitatory activity was mediated by complement receptor 1-related gene/protein Y (Crry) with known MCP activity on the trophectoderm of the embryos as anti-Crry antibody inhibited the conversion and embryotrophic activity of C3b in the presence of factor-I. In conclusion, human oviduct possesses C3 convertase activity converting C3 to C3b, and Crry of the preimplantation embryos may be involved in the production of embryotrophic iC3b on the surface of the embryos. [Abstract/Link to Full Text]

Yamada C, Yamada Y, Tsukiyama K, Yamada K, Udagawa N, Takahashi N, Tanaka K, Drucker DJ, Seino Y, Inagaki N
The murine Glp1r is essential for control of bone resorption.
Endocrinology. 2007 Nov 26;
Gastrointestinal hormones including gastric inhibitory polypeptide (GIP), glucagon-like peptide-1 (GLP-1), and glucagon-like peptide-2 (GLP-2) are secreted immediately after meal ingestion, and GIP and GLP-2 have been shown to regulate bone turnover. We hypothesize that endogenous GLP-1 may also be important for control of skeletal homeostasis. We investigated the role of GLP-1 in the regulation of bone metabolism using GLP-1 receptor knockout (Glp-1r(-/-)) mice. A combination of bone density and histomorphometry, osteoclast activation studies, biochemical analysis of calcium and parathyroid hormone, and RNA analysis was used to characterize bone and mineral homeostasis in Glp-1r(-/-) and Glp-1r(+/+) littermate controls. Glp-1r(-/-) mice have cortical osteopenia and bone fragility by bone densitometry, as well as increased osteoclastic numbers and bone resorption activity by bone histomorphometry. Although GLP-1 had no direct effect on osteoclasts and osteoblasts, Glp-1r(-/-) mice exhibited higher levels of urinary deoxypyridinoloine (DPD), a marker of bone resorption, and reduced levels of calcitonin mRNA transcripts in the thyroid. Moreover, calcitonin treatment effectively suppressed urinary levels of DPD in Glp-1r(-/-) mice and the GLP-1 receptor agonist exendin-4 increased calcitonin gene expression in the thyroid of wildtype mice. These findings establish an essential role for endogenous GLP-1 receptor signaling in the control of bone resorption, likely through a calcitonin-dependent pathway. [Abstract/Link to Full Text]

Bouskine A, Nebout M, Mograbi B, Br�cker-Davis F, Roger C, Fenichel P
Estrogens promote human testicular germ cell cancer through a membrane-mediated activation of Extra-cellular Regulated Kinase and Protein kinase-A.
Endocrinology. 2007 Nov 26;
Clinical and experimental studies have suggested that estrogens, the archetype of female hormones, participate in the control of male germ cell proliferation and that fetal exposure to environmental estrogens may contribute to hypofertility and/or to testicular germ cell cancer (TGCT). However the underlying mechanisms remain to be elucidated. Estradiol 17beta conjugated to bovine serum albumin (E2-BSA), was able to stimulate human testicular seminoma cell proliferation by triggering a rapid, non genomic, membrane-mediated activation of Extracellular Signal-Regulated Kinase 1/2 (ERK1/2) and Cyclic-AMP-dependent protein kinase A (PKA). Both ERK1/2 and PKA participated to this promoting effect. This activation was associated with phosphorylation of the transcription factor CREB (Cyclic AMP Response Element Binding protein) and the nuclear factor Rb (Retinoblastoma protein). Enhanced proliferation together with ERK activation could be reversed by pertussis toxin, a G protein inhibitor. Estrogen receptors (ERs) in JKT-1 were characterized by Immunofluorescence, subcellular fractioning, and Western blot. JKT-1 cells did not express ERalpha but ERbeta which localized to the mitochondria and the nucleus but not to the membrane. Moreover neither ICI182780, a classical ER antagonist or tamoxifen, a selective estrogen receptor modulator, could reverse E2-BSA induced promoting effect. Estrogens contribute to human testicular germ cell cancer proliferation by rapid activation of ERK1/2 and PKA through a membrane non classical estrogen receptor. This non genomic effect represents a new basis for understanding the estrogenic control of spermatogenesis and evaluating the role of fetal exposure to xenoestrogens during malignant transformation of testicular germ stem cells. [Abstract/Link to Full Text]

Ladenheim EE, Hamilton NL, Behles RR, Bi S, Hampton LL, Battey JF, Moran TH
Factors contributing to obesity in bombesin receptor subtype-3 deficient mice.
Endocrinology. 2007 Nov 26;
Mice with a targeted disruption of bombesin receptor subtype-3 (BRS-3 KO) develop hyperphagia, obesity, hypertension and impaired glucose metabolism. However, the factors contributing to their phenotype have not been clearly established. To determine whether their obesity is a result of increased food intake or a defect in energy regulation we matched the caloric intake of BRS-3 KO mice to wild-type (WT) ad lib fed controls over 21 weeks. Although BRS-3 KO ad lib fed mice were 29% heavier, the body weights of BRS-3 KO pair-fed mice did not differ from WT ad lib fed mice. Pair-feeding BRS-3 KO mice normalized plasma insulin but failed to completely reverse increased adiposity and leptin levels. Hyperphagia in ad lib fed KO mice was due to an increase in meal size without a compensatory decrease in meal frequency resulting in an increase in total daily food intake. An examination of neuropeptide Y, pro-opiomelanocortin and agouti-related peptide gene expression in the arcuate nucleus revealed that BRS-3 KO mice have some deficits in their response to energy regulatory signals. An evaluation of the satiety effects of cholecystokinin, bombesin and gastrin-releasing peptide found no differences in feeding suppression by these peptides. We conclude that hyperphagia is a major factor leading to increased body weight and hyperinsulinemia in BRS-3 KO mice. However, our finding that pair-feeding did not completely normalize fat distribution and plasma leptin levels suggests there is also a metabolic dysregulation that may contribute to, or sustain, their obese phenotype. [Abstract/Link to Full Text]

Lam DD, Przydzial MJ, Ridley SH, Yeo GS, Rochford JJ, O'Rahilly S, Heisler LK
Serotonin 5-HT2C Receptor Agonist Promotes Hypophagia via Downstream Activation of Melanocortin 4 Receptors.
Endocrinology. 2007 Nov 26;
The neurotransmitter serotonin (5-hydroxytryptamine, 5-HT) is a well established modulator of energy balance. Both pharmacological and genetic evidence implicate the serotonin 2C receptor (5-HT2CR) as a critical receptor mediator of serotonin's effects on ingestive behavior. Here we characterize the effect of the novel and selective 5-HT2CR agonist BVT.X on energy balance in obese and lean mice and report that BVT.X significantly reduces acute food intake without altering locomotor activity or oxygen consumption. In an effort to elucidate the mechanism of this effect, we examined the chemical phenotype of 5-HT2CR-expressing neurons in a critical brain region affecting feeding behavior, the arcuate nucleus of the hypothalamus (ARC). We show that 5-HT2CRs are co-expressed with neurons containing proopiomelanocortin (POMC), known to potently affect appetite, in the ARC of the mouse. We then demonstrate that prolonged infusion with BVT.X in obese mice significantly increases Pomc mRNA and reduces body weight, %body fat, and initial food intake. To evaluate the functional importance of melanocortin circuitry in the effect of BVT.X on ingestive behavior, we assessed mice with disrupted melanocortin pathways. We report that mice lacking the melanocortin 4 receptor (MC4R) are not responsive to BVT.X-induced hypophagia, demonstrating that melanocortins acting on MC4R are a requisite downstream pathway for 5-HT2CR agonists to exert effects on food intake. The data presented here not only indicate that the novel 5-HT2CR agonist BVT.X warrants further investigation as a treatment for obesity, but also elucidate specific neuronal pathways potently affecting energy balance through which 5-HT2CR agonists regulate ingestive behavior. [Abstract/Link to Full Text]

Sun Y, Butte NF, Garcia JM, Smith RG
Characterization of adult ghrelin and ghrelin receptor knockout mice under positive and negative energy balance.
Endocrinology. 2007 Nov 15;
Ghrelin and the ghrelin receptor (growth hormone secretagogue receptor, GHS-R), are believed to have important roles in energy homeostasis. We describe results from the first studies to be conducted in congenic (N10) adult ghrelin-/- and Ghsr-/- mice under conditions of both positive (high fat diet) and negative (caloric restriction) energy balance. In contrast to results from young N2 mutant mice, changes in body weight and energy expenditure are not clearly distinguishable across genotypes. Although RQ was lower in mice fed a high fat diet, no differences were evident between littermate wild-type (WT) and null genotypes. With normal chow, a modest decrease trend in respiratory quotient (RQ) was detected in ghrelin-/- mice, but not in Ghsr-/- mice. Under caloric restriction, the weight loss of ghrelin-/- and Ghsr-/- mice was identical to WT littermates, but blood glucose levels were significantly lower. We conclude that adult congenic ghrelin-/- and Ghsr-/- mice are not resistant to diet-induced obesity, but under conditions of negative energy balance show impairment in maintaining glucose homeostasis. These results support our hypothesis that the primary metabolic function of ghrelin in adult mice is to modulate glucose sensing and insulin sensitivity, rather than directly regulate energy intake and energy expenditure. [Abstract/Link to Full Text]

Soulage C, Zarrouki B, Soares AF, Lagarde M, Geloen A
Lou/C obesity resistant rat exhibits hyperactivity, hypermetabolism, alterations in white adipose tissue cellularity and lipid tissue profiles.
Endocrinology. 2007 Nov 15;
Lou/C obesity resistant rat constitutes an original approach to understand the phenomena of overweight and obesity. The aim of the present study was to identify metabolic causes for the outstanding leanness of Lou/C rat. To this end, the metabolic profiles (food intake, energy expenditure and physical activity) and the cellular characteristics of white adipose tissue (lipogenesis, lipolysis, cellularity and lipid composition) in thirty-weeks-old Lou/C rats were compared to age matched Wistar rats. Lou/C rats exhibited a lower body weight (-45%), a reduced adiposity (-80%), an increased locomotor activity (+95%) and a higher energy expenditure (+11%) than Wistar rats. Epididymal adipose tissue of Lou/C rat was twice lower than that of Wistar rat due to both a reduction in adipocytes size (-25%) and number (3-times). Basal lipolysis and sensitivity to noradrenaline were similar; however the responsiveness to noradrenaline was lower in adipocytes from Lou/C compared to that from Wistar rats. Lipidomic analysis of plasma, adipose tissue and liver revealed profound differences in lipid composition between the two strains. Of note, the desaturation indexes (ratio C16:1/C16:0 and C18:1/C18:0) were lower in Lou/C indicating a blunted activity of delta-9-desaturase such as Stearoyl-CoA-desaturase-1. Increased physical activity, increased energy expenditure and white adipose tissue cellularity are in good agreement with previous observations suggesting that a higher sympathetic tone in Lou/C could contribute to its lifelong leanness. [Abstract/Link to Full Text]

Wang X, Yin X, Schiffer RB, King SR, Stocco DM, Grammas P
Inhibition of Thromboxane A Synthase Activity Enhances Steroidogenesis and Steroidogenic Acute Regulatory Gene Expression in MA-10 Mouse Leydig Cells.
Endocrinology. 2007 Nov 15;
The cyclooxygenase-2 (COX2)-dependent inhibition of Leydig cell steroidogenesis has been demonstrated. To understand the mechanism for this effect of COX2, the present study examined the role of an enzyme downstream of COX2, namely thromboxane A synthase (TBXAS), in steroidogenesis. Inhibition of TBXAS activity with the inhibitor furegrelate induced a concentration-dependent increase in cAMP-induced steroidogenic acute regulatory (StAR) protein in MA-10 mouse Leydig cells. The increase in StAR protein occurred concomitantly with a significant increase in steroid hormone production. Similar results were obtained in StAR promoter activity assays and RT-PCR analyses of StAR mRNA levels, suggesting that inhibition of TBXAS activity enhanced StAR gene transcription. These observations were corroborated when TBXAS expression was specifically inhibited by RNA interference (RNAi). While the RNAi reduced mRNA levels of TBXAS, it increased StAR mRNA levels, StAR protein and steroidogenesis. Additional studies indicated that inhibition of TBXAS activity reduced DAX-1 protein, a repressor in StAR gene transcription. In the absence of cAMP, inhibition of TBXAS activity did not induce a significant increase in steroid hormone and StAR protein. However, addition of a low level of cAMP analogs dramatically increased steroidogenesis. Lastly, inhibition of protein kinase A (PKA) activity essentially abolished the steroidogenic effect of the TBXAS inhibitor. Thus, the results from the present study suggest that a minimal level of PKA activity is required for the steroidogenic effect of the TBXAS inhibitor and that inhibition of TBXAS activity or its expression increase the steroidogenic sensitivity of MA-10 mouse Leydig cells to cAMP stimulation. [Abstract/Link to Full Text]

Aga-Mizrachi S, Brutman-Barazani T, Jacob AI, Bak A, Elson A, Sampson SR
Cytosolic Protein Tyrosine Phosphatase {epsilon} (cytPTP{epsilon}) is a Negative Regulator of Insulin Signaling in Skeletal Muscle.
Endocrinology. 2007 Nov 15;
While positive regulatory events triggered by insulin binding to insulin receptor (IR) have been well documented, the mechanism by which the activated IR is returned to the basal status is not completely understood. Recently, studies have focused on the involvement of protein tyrosine phosphatases (PTPs) and how they might influence IR signaling. In this study, we examined the possibility that cytosolic PTPepsilon (cytPTPepsilon) is involved in IR signaling. Studies were performed on L6 skeletal muscle cells. cytPTPepsilon was over expressed by using pBABE retroviral expression vectors. In addition, we inhibited cytPTPepsilon by RNA silencing. We found that insulin induced rapid association of cytPTPepsilon with IR. Interestingly, this association appeared to occur in the plasma membrane, and on stimulation with insulin the two proteins internalized together. Moreover, it appeared that almost all internalized IR was associated with cytPTPepsilon. We found that knockdown of cytPTPepsilon by RNA silencing increased insulin-induced tyrosine phosphorylation of IR, IRS-1, as well as phosphorylation of PKB and GSK3, and insulin-induced stimulation of glucose uptake. Moreover, overexpression of WT cytPTPepsilon reduced insulin-induced tyrosine phosphorylation of IR, IRS-1, as well as phosphorylation of PKB and GSK3, and insulin-induced stimulation of glucose uptake. Finally, insulin-induced tyrosine phosphorylation of IR and IRS-1 was greater in skeletal muscle from mice lacking the cytPTPepsilon gene than that from wild type control animals. We conclude that cytoplasmic PTPepsilon (cytPTPepsilon) serves as another major candidate negative regulator of IR signaling in skeletal muscle. [Abstract/Link to Full Text]

Bernichtein S, Petretto E, Jamieson S, Goel A, Aitman TJ, Mangion JM, Huhtaniemi IT
Adrenal gland tumorigenesis after gonadectomy in mice is a complex genetic trait driven by epistatic loci.
Endocrinology. 2007 Nov 15;
Post-gonadectomy adrenocortical tumorigenesis is a strain-specific phenomenon in inbred mice, assumed to be caused by elevated luteinizing hormone (LH) secretion and subsequent ectopic LH receptor (LHR) overexpression in adrenal gland. However, the molecular mechanisms of this cascade of events remain unknown. In this study, we took advantage of the mouse strain-dependency of the phenotype to unravel its genetic basis. Our results present the first genome-wide screening related to this pathology in two independent F2 and backcross populations generated between the neoplastic DBA/2J and the non-susceptible C57BL/6J strains. Surprisingly, the post-gonadectomy elevation of serum LH was followed by similar up-regulation of adrenal LHR expression in both parental strains and their crosses, irrespective of their tumor status, indicating that it is not the immediate cause of the tumorigenesis. Linkage analysis revealed one major significant locus for the tumorigenesis on chromosome 8, modulated by epistasis with another QTL on chromosome 18. Weight gain, a secondary phenotype after gonadectomy, showed a significant but separate QTL on chromosome 7. Altogether, post-gonadectomy adrenocortical tumorigenesis in DBA/2J mice is a dominant trait which is not a direct consequence of adrenal LHR expression but is driven by a complex genetic architecture. Analysis of candidate genes in the tumorigenesis linkage region showed that Sfrp1 (secreted frizzled related protein 1), a tumor suppressor gene, is differentially expressed in the neoplastic areas. These findings may have relevance to the human pathogenesis of macronodular adrenal hyperplasia and adrenocortical tumors in post-menopausal women, and why some of them develop obesity. [Abstract/Link to Full Text]

Northrop LE, Erskine MS
Selective Oxytocin Receptor Activation in the Ventrolateral Portion of the Ventromedial Hypothalamus Is Required for Mating-induced Pseudopregnancy in the Female Rat.
Endocrinology. 2007 Nov 15;
The ventrolateral region of the ventromedial hypothalamus (VMHvl) plays an essential role in female sexual behavior. Oxytocin (OT) is released from the paraventricular nucleus to downstream sites such as the VMHvl to facilitate female sexual behavior and shows characteristics of a prolactin-releasing factor. During mating, vaginal cervical stimulation (VCS) received from a vasectomized male triggers twice daily prolactin (PRL) surges which persist up to 12+ days, a period known as pseudopregnancy (PSP). To determine whether OT is involved in PSP by acting within the VMHvl, female rats were infused bilaterally with either an oxytocin receptor antagonist (OTR-A), a vasopressin receptor antagonist (V1a-A) or artificial cerebral spinal fluid (aCSF) 30 min prior to mating. All females received a sufficient amount of VCS, 15 intromissions, to induce PSP. Females infused with OTR-A (20 ng/0.4 microl) with implants targeting the VMHvl showed only a 22% induction of PSP, as measured using vaginal diestrus and serum PRL concentrations. In contrast, controls and V1a-A (80 ng/0.4 microl) infused females exhibited 100% induction of PSP. Females infused with OTR-A returned to estrus after 5 days, whereas females infused with either aCSF or V1a-A remained in diestrus for 12-13 days in both the correct and missed placement groups. Although OT can act as a prolactin releasing factor, the PRL surge does not begin until 18-24 h after mating. Taken together, our results suggest that OT release in the VMHvl mediates the effects of VCS on the induction of the PRL secretion needed to establish PSP. [Abstract/Link to Full Text]

Adamson AD, Friedrichsen S, Semprini S, Harper CV, Mullins JJ, White MR, Davis JR
Human Prolactin Gene Promoter Regulation by Estrogen Convergence with TNF{alpha} Signaling.
Endocrinology. 2007 Nov 15;
Estrogens have been implicated in the regulation of prolactin gene expression in man, although previous studies have not defined the molecular mechanism whereby estradiol activates the human prolactin gene promoter (hPrl). We found that estradiol induced a reproducible 1.8-fold activation of the hPrl gene promoter, using pituitary GH3 cells stably transfected with a 5000bp hPrl promoter fragment linked to luciferase reporter gene. This activation was blocked by treatment with ER antagonists 4-hydroxytamoxifen and ICI-182,780. Promoter deletion and mutagenesis experiments identified a functional Estrogen response element (ERE) sequence 1189bp upstream of the transcription start site that was responsible for estrogen mediated promoter activation. This site differed from the consensus ERE sequence by two base pairs, one in each half site. This ERE was identified to be functional through binding ERalpha in electrophoretic mobility shift assays. ChIP assays confirmed ERalpha binding to this sequence in vivo in the absence of ligand, with increased recruitment when cells were cultured in the presence of estradiol. When cells were treated with both estradiol and TNFalpha we observed synergistic activation of the hPrl promoter, which was mediated by the -1189bp ERE. Mutagenesis of this ERE abolished the promoter activating effect not only of estradiol, but also that of TNFalpha. These data suggest a novel, promoter specific signaling interaction between estrogen and TNFalpha signaling, which is likely to be important for prolactin regulation in vivo. [Abstract/Link to Full Text]

Herbison AE, Porteous R, Pape JR, Mora JM, Hurst PR
Gonadotropin-releasing hormone (GnRH) neuron requirements for puberty, ovulation and fertility.
Endocrinology. 2007 Nov 15;
The absolute requirement for reproduction implies that hypothalamo-pituitary-gonadal axis, controlling fertility, is an evolutionary robust mechanism. The gonadotropin-releasing hormone (GnRH) neurons of the hypothalamus represent the key cell type within the body dictating fertility. However, the level of functional redundancy within the GnRH neuron populations is unknown. As a result of a fortuitous transgene insertion event, GNR23 mice exhibit a marked allele-dependent reduction in GnRH neuron number within their brain. Wild-type mice have approximately 600 GnRH neurons compared with approximately 200 (34%) and approximately 70 (12%) in GNR23+/- and GNR23-/- mice, respectively. Using these mice we have examined the minimal GnRH neuron requirements for fertility. Male GNR23-/- mice exhibited normal fertility. In contrast, female GNR23-/- mice were markedly sub-fertile, failing to produce normal litters, estrous cycles or ovulate. The failure of ovulation resulted from an inability of the few existing GnRH neurons to generate the luteinizing hormone surge. This was not the case, however, for the first cycle at puberty that appeared normal. Together, these observations demonstrate that 12% of the GnRH neuron population is sufficient for pulsatile gonadotropin secretion and puberty onset, whereas between 12 and 34% are required for cyclical control in adult female mice. This indicates that substantial redundancy exists within the GnRH neuronal population and suggests that the great majority of GnRH neurons must be dysfunctional before fertility is affected. [Abstract/Link to Full Text]

van der Laan S, Lachize SB, Vreugendhil E, de Kloet ER, Meijer OC
Nuclear receptor coregulators differentially modulate CREB-mediated induction and glucocorticoid receptor mediated repression of the CRH gene.
Endocrinology. 2007 Nov 15;
Nuclear receptor coregulators are proteins that modulate the transcriptional activity of steroid receptors, and may explain cell specific effects of glucocorticoid receptor action. Based on the uneven distribution of a number of coregulators in corticotropin-releasing hormone (CRH) expressing cells in the hypothalamus of the rat brain, we tested the hypothesis that these proteins are involved as mediators in the glucocorticoid induced repression of the CRH promoter. Therefore, we have assessed the role of the steroid receptor coactivator 1a (SRC1a), SRC-1e, and corepressors N-CoR and SMRT on both induction and repression of CRH in the AtT-20 cell-line, a model system for CRH repression by glucocorticoids. We show that the concentration of glucocorticoid receptor and the type of ligand, i.e. corticosterone or dexamethasone, determines the repression. Furthermore, overexpression of SRC1a, but not SRC1e, increased both efficacy and potency of the glucocorticoid receptor mediated repression of the forskolin-induced CRH promoter. Unexpectedly, co-transfection of the corepressors N-CoR and SMRT did not affect the corticosterone-dependent repression, but resulted in a marked decrease of the forskolin stimulation of the CRH gene. Altogether, our data demonstrate that 1) the concentration of the receptor, 2) the type of ligand and 3) the coregulator recruited, all determine the expression and the repression of the CRH gene. We conclude that modulation of coregulator activity may play a role in the control of the hypothalamus-pituitary-adrenal axis. [Abstract/Link to Full Text]

Clasadonte J, Poulain P, Beauvillain JC, Prevot V
Activation of neuronal nitric oxide release inhibits spontaneous firing in adult gonadotropin-releasing hormone neurons: A possible local synchronizing signal.
Endocrinology. 2007 Nov 15;
The activation of nitric oxide (NO) signaling pathways in hypothalamic neurons plays a key role in the control of gonadotropin-releasing hormone (GnRH) secretion that is central to reproductive function. It is unknown whether NO directly modulates the firing behavior of GnRH neurons in the preoptic region of the mature brain. Using patch-clamp recordings from GnRH neurons expressing green fluorescent protein in adult mice brain slices, we demonstrate that the NO precursor, L-arginine, or the NO donor, DEA/NO, induced a robust and reversible reduction in the spontaneous firing activity of GnRH neurons, including bursting activity. The effects of L-arginine were prevented by the NO synthase (NOS) inhibitor L-NAME. Histochemical studies revealing a close anatomical relationship between neurons producing NO and GnRH perikarya, together with the loss of the L-arginine-mediated inhibition of GnRH neuronal activity via the selective blockade of neuronal NOS, suggested that the primary source of local NO production in the mouse preoptic region was neuronal. Synaptic transmission uncoupling did not alter the effect of NO, suggesting that NO affects the firing pattern of GnRH neurons by acting at a postsynaptic site. We also show that the NO-mediated changes in membrane properties in the GnRH neurons require soluble guanylyl cyclase activity and may involve potassium conductance. By revealing that NO is a direct modulator of GnRH neuronal activity, our results introduce the intriguing possibility that this gaseous neurotransmitter may be used by the sexual brain to modulate burst firing patterns. It may set into phase the bursting activity of GnRH neurons at key stages of reproductive physiology. [Abstract/Link to Full Text]

Delahaye F, Breton C, Risold PY, Enache M, Dutriez-Casteloot I, Laborie C, Lesage J, Vieau D
Maternal Perinatal Undernutrition Drastically Reduces Postnatal Leptin Surge and Affects the Development of Arcuate Nucleus POMC Neurons in Neonatal Male Rat Pups.
Endocrinology. 2007 Nov 15;
A growing body of evidence suggests that maternal undernutrition sensitizes the offspring to the development of energy balance metabolic disorders such as type 2 diabetes, dyslipidemia and obesity. The present study aimed at examining the impact of maternal undernutrition on leptin plasma levels in newborn male rats and on the arcuate nucleus proopiomelanocortin (POMC) and neuropeptide Y (NPY) neurons that are major leptin targets. Using a model of perinatal maternal 50% food-restricted diet (FR50) in rat, we evaluated leptin plasma levels and hypothalamic POMC and NPY gene expression from postnatal day (PND) 4 to PND30 in both control and FR50 offspring. In control rats, a postnatal peak of plasma leptin was observed between PND4 and PND14 that reached a maximal value at PND10 (5.17 +/- 0.53 ng/mL) whereas it was dramatically reduced in FR50 pups with the higher concentration at PND7 (0.93 +/- 0.23 ng/mL). In FR50 animals, using semi-quantitative RT-PCR and in situ hybridization, we showed that hypothalamic POMC mRNA level was decreased from PND14 until PND30, whereas NPY gene expression was not significantly modified. In PND21 FR50 animals, we observed strikingly reduced immunoreactive beta-endorphin nerve fibers projecting to the hypothalamic paraventricular nucleus without affecting NPY projections. Our data showed that maternal undernutrition drastically reduces the postnatal surge of plasma leptin disturbing, particularly the hypothalamic wiring as well as the gene expression of the anorexigenic POMC neurons in male rat pups. These alterations might contribute to the adult metabolic disorders resulting from perinatal growth retardation. [Abstract/Link to Full Text]

Recent Articles in Molecular Endocrinology

He B, Feng Q, Mukherjee A, Lonard DM, Demayo FJ, Katzenellenbogen BS, Lydon JP, O'malley BW
A Repressive Role for Prohibitin in Estrogen Signaling.
Mol Endocrinol. 2007 Oct 11; .
Nuclear receptor-mediated gene expression is regulated by corepressors and coactivators. In this study we demonstrate that prohibitin (PHB), a potential tumor suppressor, functions as a potent transcriptional corepressor for estrogen receptor alpha (ERalpha). Overexpression of PHB inhibits ERalpha transcriptional activity while depletion of endogenous PHB increases the expression of ERalpha target genes in MCF-7 breast cancer cells. Chromatin immunoprecipitation experiments demonstrate that PHB is associated with the estrogen-regulated pS2 promoter in the absence of hormone and dissociates after estradiol treatment. We demonstrate that PHB interacts with the repressor of estrogen receptor activity (REA), a protein related to PHB, to form heteromers and enhance the protein stability of both corepressors. Interestingly, the corepressor activity of PHB is cross-squelched by the co-expression of REA (and vice versa), suggesting that PHB and REA repress transcription only when they are not paired. We further demonstrate that coiled-coil domains located in the middle of PHB and REA are responsible for their heteromerization, stabilization, and cross-squelching actions. Finally ablation of PHB function in the mouse results in early embryonic lethality whereas mice heterozygous for the PHB null allele exhibit a hyperproliferative mammary gland phenotype. Our results indicate that PHB functions as a transcriptional corepressor for ERalpha in vitro and in vivo, and that its heteromerization with REA acts as a novel mechanism to limit its corepressor activity. [Abstract/Link to Full Text]

Kim PS, Lee J, Jongsamak P, Menon S, Li B, Hossain SA, Bae JH, Panijpan B, Arvan P
Defective Protein Folding and Intracellular Retention of Thyroglobulin-R19K Mutant as a Cause of Human Congenital Goiter.
Mol Endocrinol. 2007 Oct 4;
It has been suggested that a thyroglobulin (Tg)-R19K missense mutation may be a newly-identified cause of human congenital goiter, which is suprising for this seemingly conservative substitution. Here, we have examined the intracellular fate of recombinant mutant Tg expressed in COS-7 cells. Incorporation of the R19K mutation largely blocked Tg secretion, and this mutant was approximately 90% degraded intracellularly over a 24 h period following synthesis. Prior to its degradation, the Tg-R19K mutant exhibited abnormally increased association with molecular chaperones BiP, calnexin, and protein disulfide isomerase, and was unable to undergo anterograde advance from the endoplasmic reticulum (ER) through the Golgi complex. Inhibitors of proteasomal proteolysis and ER mannosidase-I both prevented ER-associated degradation of the Tg-R19K mutant and increased its association with ER molecular chaperones. ER quality control around Tg residue 19 is not dependent upon charge but upon side-chain packing, as Tg-R19Q was efficiently secreted. While a Tg mutant truncated after residue 174 folds sufficiently well to escape ER quality control, introduction of the R19K point mutation blocked its secretion. The data indicate that the R19K mutation induces local misfolding in the amino-terminal domain of Tg that has global effects on Tg transport and thyroid hormonogenesis. [Abstract/Link to Full Text]

Kilkenny DM, Rocheleau JV
Fibroblast Growth Factor Receptor-1 Signaling in Pancreatic Islet {beta}-cells is Modulated by the Extracellular Matrix.
Mol Endocrinol. 2007 Oct 4;
Maintenance of pancreatic beta-cell mass depends on extracellular stimuli that promote survival and proliferation. In the islet, these stimuli come from the beta-cell microenvironment and include extracellular matrix (ECM) deposited by associated vascular endothelial cells. Fibroblast growth factor receptor-1 (FGFR1) has recently been implicated as a signaling pathway that is important for normal beta-cell function. We would like to understand how ECM- and FGFR1-signaling interact to promote beta-cell survival and proliferation. To examine beta-cell-specific receptor responses, we created lentiviral vectors with rat insulin promoter-driven expression of Venus fluorescent protein-tagged full-length (R1betav) and kinase-deficient (KDR1betav) FGFR1. Significant FGF-1-dependent activation of ERK1/2 was observed in betaTC3 cells, dispersed beta-cells and beta-cells in intact islets. This response was enhanced by R1betav expression and reduced by KDR1betav expression. Plating dispersed beta-cells on collagen type IV resulted in enhanced expression of endogenous FGFR1 that was associated with sustained activation of ERK1/2. Conversely, plating cells on laminin reduced expression of FGFR1 and this reduction was associated with transient activation of ERK1/2. Addition of neutralizing antibodies to inhibit beta-cell attachment to laminin via alpha6-integrin increased high-affinity FGF-1-binding at the plasma membrane and resulted in sustained ERK1/2 activity similar to cells plated on collagen type IV. These data show that the FGF-stimulated beta-cell response is negatively affected by alpha6-integrin binding to laminin, and suggest regulation associated with vascular endothelial cell remodeling. [Abstract/Link to Full Text]

Hou X, Arvisais EW, Jiang C, Chen DB, Roy SK, Pate JL, Hansen TR, Rueda BR, Davis JS
Prostaglandin F2{alpha} (PGF2{alpha}) Stimulates the Expression and Secretion of TGFB1via Induction of the Early Growth Response 1 Gene (EGR1) in the Bovine Corpus Luteum.
Mol Endocrinol. 2007 Oct 4;
In most mammals, prostaglandin F2alpha (PGF2alpha) is believed to be a trigger that induces the regression of the corpus luteum (CL), whereby progesterone synthesis is inhibited, the luteal structure involutes, and the reproductive cycle resumes. Studies have shown that the early growth response 1 (EGR1) protein can induce the expression of pro-apoptotic proteins, suggesting that EGR1 may play a role in luteal regression. Our hypothesis is that EGR1 mediates the actions of PGF2alpha by inducing the expression of transforming growth factor beta 1 (TGFB1), a key tissue remodeling protein. The levels of EGR1 mRNA and protein were up-regulated in the bovine CL during PGF2alpha-induced luteolysis in vivo and in PGF2alpha-treated luteal cells in vitro. Using chemical and genetic approaches, the RAF/MEK1/ERK pathway was identified as a proximal signaling event required for the induction of EGR1 in PGF2alpha-treated cells. Treatment with PGF2alpha increased the expression of TGFB1 mRNA and protein as well as the binding of EGR1 protein to TGFB1 promoter in bovine luteal cells. The effect of PGF2alpha on TGFB1 expression was mimicked by a PKC/RAF/MEK1/ERK activator or adenoviral-mediated expression of EGR1. The stimulatory effect of PGF2alpha on TGFB1 mRNA and TGFB1 protein secretion was inhibited by blockade of MEK1/ERK signaling and by adenoviral-mediated expression of NAB2, an EGR1 binding protein that inhibits EGR1 transcriptional activity. Treatment of luteal cells with TGFB1 reduced progesterone secretion, implicating TGFB1 in luteal regression. These studies demonstrate that PGF2alpha stimulates the expression of EGR1 and TGFB1 in the CL. We suggest that EGR1 plays a role in the expression of genes whose cognate proteins coordinate luteal regression. [Abstract/Link to Full Text]

Lewis AE, Rusten M, Hoivik EA, Vikse EL, Hansson ML, Wallberg AE, Bakke M
Phosphorylation of steroidogenic factor 1 is mediated by CDK7.
Mol Endocrinol. 2007 Sep 27;
The nuclear receptor steroidogenic factor-1 (SF1) is critical for development and function of steroidogenic tissues. Posttranslational modifications are known to influence the transcriptional capacity of SF1, and it was previously demonstrated that serine 203 (S203) is phosphorylated. In this paper we report that S203 is phosphorylated by a cyclin dependent kinase 7 (CDK7)-mediated process. As part of the CDK-activating kinase (CAK) complex, CDK7 is a component of the basal transcription factor TFIIH, and phosphorylation of SF1 as well as SF1-dependent transcription was clearly reduced in cells carrying a mutation that renders the CAK complex unable to interact with the TFIIH core. Co-immunoprecipitation analyses revealed that SF1 and CDK7 reside in the same complex, and kinase assays demonstrated that immunoprecipitated CDK7 and purified TFIIH phosphorylate SF1 in vitro. The CDK-inhibitor roscovitine blocked phosphorylation of SF1 and an inactive form of CDK7 repressed the phosphorylation level and the transactivation capacity of SF1. Structural studies have identified phosphoinositides as potential ligands for SF1. Interestingly, we found that mutations designed to block phospholipid binding dramatically decreased the level of SF1 phosphorylation. Together our results suggest a connection between ligand occupation and phosphorylation and association with the basic transcriptional machinery, indicating an intricate regulation of SF1 transactivation. [Abstract/Link to Full Text]

Gao H, F�lt S, Sandelin A, Gustafsson JA, Dahlman-Wright K
Genome-wide identification of estrogen receptor {alpha} binding sites in mouse liver.
Mol Endocrinol. 2007 Sep 27;
We report the genome-wide identification of estrogen receptor alpha (ERalpha) binding regions in mouse liver using a combination of chromatin immunoprecipitation (ChIP) and tiled microarrays that cover all non-repetitive sequences in the mouse genome. This analysis identified 5568 ERalpha binding regions. In agreement with what has previously been reported for human cell lines, many ERalpha binding regions are located far away from transcription start sites; approximately 40% of ERalpha binding regions are located within 10kb of annotated transcription start sites. Almost 50% of ERalpha binding regions overlap genes. The majority of ERalpha binding regions lie in regions that are evolutionary conserved between human and mouse. Motif-finding algorithms identified the estrogen response element (ERE), and variants thereof, together with binding sites for activator protein 1 (AP1), basic-helix-loop-helix (bHLH) proteins, ETS proteins and Forkhead proteins as the most common motifs present in identified ERalpha binding regions. To correlate ERalpha binding to the promoter of specific genes, with changes in expression levels of the corresponding mRNAs, expression levels of selected mRNAs were assayed in livers 2 h, 4 h and 6 h after treatment with ERalpha selective agonist propyl pyrazole triol (PPT). Five of these 8 selected genes, Shp, Stat3, Pdgds, Pck1 and Pdk4 all responded to PPT after 4 h treatment. These results extend our previous studies using gene expression profiling to characterize estrogen signaling in mouse liver, by characterizing the first step in this signaling cascade, the binding of ERalpha to DNA in intact chromatin. [Abstract/Link to Full Text]

Zhang Y, McKeehan K, Lin Y, Zhang J, Wang F
FGFR1 tyrosine phosphorylation regulates binding of FRS2alpha but not FRS2beta to the receptor.
Mol Endocrinol. 2007 Sep 27;
Binding of the fibroblast growth factor (FGF) to the FGF receptor (FGFR) tyrosine kinase leads to receptor tyrosine autophosphorylation, as well as phosphorylation of multiple downstream signaling molecules that are recruited to the receptor either by direct binding or through adaptor proteins. The FGFR substrate 2 (FRS2) family consists of two members, FRS2alpha and FRS2beta, and has been shown to recruit multiple signaling molecules, including Grb2 and Shp2, to FGFR1. To better understand how FRS2 interacted with FGFR1, in vivo binding assays with coexpressed FGFR1 and FRS2 recombinant proteins in mammalian cells were carried out. The results showed that the interaction of full-length FRS2alpha, but not FRS2beta, with FGFR1 was enhanced by activation of the receptor kinase. The truncated FRS2alpha mutant that was only comprised of the phosphotyrosine binding domain (PTB) bound FGFR1 constitutively, suggesting that the C-terminal sequence downstream the PTB domain inhibited the PTB-FGFR1 binding. Inactivation of the FGFR1 kinase and substitutions of tyrosine phosphorylation sites of FGFR1, but not FRS2alpha, reduced binding of FGFR1 with FRS2alpha. The results suggest that although the tyrosine autophosphorylation sites of FGFR1 did not constitute the binding sites for FRS2alpha, phosphorylation of these residues was essential for optimal interaction with FRS2alpha. In addition, it is demonstrated that the Grb2-binding sites of FRS2alpha are essential for mediating signals of FGFR1 to activate the FiRE enhancer of the mouse syndecan 1 gene. The results, for the first time, demonstrate the specific signals mediated by the Grb2-binding sites, and further our understanding of FGF signal transmission at the adaptor level. [Abstract/Link to Full Text]

Li W, Sun G, Yang S, Qu Q, Nakashima K, Shi Y
Nuclear receptor TLX regulates cell cycle progression in neural stem cells of the developing brain.
Mol Endocrinol. 2007 Sep 27;
TLX is an orphan nuclear receptor that is expressed exclusively in vertebrate forebrains. Although TLX is known to be expressed in embryonic brains, the mechanism by which it influences neural development remains largely unknown. We show here that TLX is expressed specifically in periventricular neural stem cells in embryonic brains. Significant thinning of neocortex was observed in E14.5 TLX-null brains with reduced nestin labeling and decreased cell proliferation in the germinal zone. Cell cycle analysis revealed both prolonged cell cycles and increased cell cycle exit in TLX-null embryonic brains. Increased expression of a cyclin-dependent kinase inhibitor p21 and decreased expression of cyclin D1 provide a molecular basis for the deficiency of cell cycle progression in embryonic brains of TLX-null mice. Furthermore, transient knockdown of TLX by in utero electroporation led to precocious cell cycle exit and differentiation of neural stem cells followed by outward migration. Together these results indicate that TLX plays an important role in neural development by regulating cell cycle progression and exit of neural stem cells in the developing brain. [Abstract/Link to Full Text]

Yin Y, Huang WW, Lin C, Chen H, Mackenzie A, Ma L
Estrogen suppresses uterine epithelial apoptosis by inducing Birc1 expression.
Mol Endocrinol. 2007 Sep 27;
The decision whether or not a cell undergoes apoptosis is determined by the opposing forces of pro- and anti-apoptotic effectors. Here we demonstrate genetically that estrogen can tip this balance toward cell survival in uterine epithelial cells by inducing the expression of Birc1s, a family of anti-apoptotic proteins. In neonatal mice, both 17beta-estradiol and the potent synthetic estrogen diethylstilbestrol (DES), strongly suppress uterine epithelial apoptosis while markedly elevating Birc1 transcript level in an ER-alpha-dependent manner. The induction of Birc1s prior to any effect on apoptosis suppression and failure of DES to completely inhibit apoptosis in Birc1a-deficient uterine epithelium, indicate a functional role for Birc1a in estrogen-mediated apoptosis suppression. In ovariectomized adult mice, expression of Birc1s is also induced by ovarian hormones, suggesting a role for these proteins in normal uterine physiology. We propose that by binding to active caspases, Birc1 proteins can eliminate them through proteasome degradation. These results for the first time establish Birc1 proteins as functional targets of estrogen in suppressing apoptosis in the uterus. [Abstract/Link to Full Text]

Miura SI, Kiya Y, Kanazawa T, Imaizumi S, Fujino M, Matsuo Y, Karnik SS, Saku K
Differential Bonding Interactions of Inverse Agonists of Angiotensin II Type 1 Receptor in Stabilizing the Inactive-state.
Mol Endocrinol. 2007 Sep 27;
Although the sartan family of angiotensin II type 1 (AT1) receptor blockers (ARBs), which includes valsartan, olmesartan and losartan, have a common pharmacophore structure, their effectiveness in therapy differs. While their efficacy may be related to their binding strength, this notion has changed with a better understanding of the molecular mechanism. Therefore, we hypothesized that each ARB differs with regard to its molecular interactions with AT1 receptor in inducing inverse agonism. Interactions between valsartan and residues Ser(105), Ser(109) and Lys(199) were important for binding. Valsartan is a strong inverse agonist of constitutive inositol phosphate (IP) production by the WT and N111G mutant receptors. Substituted cysteine accessibility mapping studies indicated that valsartan, but not losartan that has only weak inverse agonism, may stabilize the N111G receptor in an inactive state upon binding. In addition, the inverse agonism by valsatan was mostly abolished with S105A/S109A/K199Q substitutions in the N111G background. Molecular modeling suggested that Ser(109) and Lys(199) bind to phenyl and tetrazole groups of valsartan, respectively. Ser(105) is a candidate for binding to the carboxyl group of valsartan. Thus, the most critical interaction for inducing inverse agonism involves transmembrane (TM) V (Lys(199)) of AT1 receptor although its inverse agonist potency is comparable to olmesartan which bonds with TM III (Tyr(113)) and TM VI (His(256)). These results provide new insights into improving ARBs and development of new G-protein coupled receptor antagonists. [Abstract/Link to Full Text]

Suh JH, Shong M, Choi HS, Lee K
CR6-interacting factor 1 represses the transactivation of androgen receptor by direct interaction.
Mol Endocrinol. 2007 Sep 20;
CR6-interacting factor 1 (CRIF1) was previously identified as a nuclear protein that interacts with members of the Gadd45 family and plays a role as a negative regulator in cell growth. However, the nuclear function of CRIF1 remains largely unknown. In this study, we demonstrate that CRIF1 acts as a novel corepressor of the androgen receptor (AR) in prostatic cells. Transient transfection studies show that CRIF1 specifically represses AR transcriptional activation of target promoters in a dose-dependent manner. Additionally, CRIF1 is recruited with AR to the endogenous AR target promoters. In vivo and in vitro protein interaction assays reveal that CRIF1 directly interacts with AR via the activation function-1 (AF-1) domain of AR. Interestingly, both the N-terminal and C-terminal half regions of CRIF1 are independently capable of interacting with and repressing the transactivation of AR. CRIF1 represses AR transactivation through competition with AR coactivators. In addition, the CRIF1-mediated inhibition of AR transactivation involves the recruitment of histone deacetylase 4 (HDAC4). Down-regulation of CRIF1 by small interfering RNA increases the transactivation of AR and the mRNA level of the AR target gene prostate-specific antigen (PSA), while the overexpression of CRIF1 decreases the prostate-specific antigen (PSA) mRNA level. Finally, the overexpression of CRIF1 inhibits the androgen-induced proliferation and cell cycle progression of prostate cancer cells. Taken together, these results suggest that CRIF1 acts as an AR corepressor, and may play an important role in the regulation of AR-positive growth of prostate cancer. [Abstract/Link to Full Text]

Kim K, Lee SH, Kim JH, Choi Y, Kim N
NFATc1 induces osteoclast fusion via up-regulation of Atp6v0d2 and DC-STAMP.
Mol Endocrinol. 2007 Sep 20;
NFATc1 has been characterized as a master regulator of RANKL-induced osteoclast differentiation. Herein, we demonstrate a novel role for NFATc1 as a positive regulator of RANKL-mediated osteoclast fusion as well as other fusion-inducing factors such as TNF-alpha. Exogenous overexpression of a constitutively active form of NFATc1 in bone marrow-derived monocyte/macrophage cells (BMMs) induces formation of multinucleated osteoclasts as well as the expression of fusion-mediating molecules such as the d2 isoform of vacuolar ATPase Vo domain (Atp6v0d2) and the dendritic cell-specific transmembrane protein (DC-STAMP). Moreover, inactivation of NFATc1 by cyclosporin A treatment attenuates expression of Atp6v0d2 and DC-STAMP and subsequent fusion process of osteoclasts. We show that NFATc1 binds to the promoter regions of Atp6v0d2 and DC-STAMP in osteoclasts and directly induces their expression. Furthermore, overexpression of Atp6v0d2 and DC-STAMP rescues cell-cell fusion of pre-osteoclasts in spite of reduced NFATc1 activity. Our data indicate for the first time that the NFATc1/Atp6v0d2 and DC-STAMP signaling axis plays a key role in the osteoclast multinucleation process, which is essential for efficient bone resorption. [Abstract/Link to Full Text]

Hwang-Verslues WW, Sladek FM
Nuclear Receptor HNF4{alpha}1 Competes with Oncoprotein c-Myc for Control of the p21/WAF1 Promoter.
Mol Endocrinol. 2007 Sep 20;
The dichotomy between cellular differentiation and proliferation is a fundamental aspect of both normal development and tumor progression; however, the molecular basis of this opposition is not well understood. To address this issue, we investigated the mechanism by which the nuclear receptor hepatocyte nuclear factor 4alpha1 (HNF4alpha1) regulates the expression of the human cyclin-dependent kinase inhibitor gene p21/WAF1 (CDKN1A). We found that HNF4alpha1, a transcription factor that plays a central role in differentiation in the liver, pancreas and intestine, activates the expression of p21 primarily by interacting with promoter-bound Sp1 at both the proximal promoter region and at newly identified sites in a distal region (-2.4 kb). Although HNF4alpha1 also binds two additional regions containing putative HNF4alpha binding sites, HNF4alpha1 mutants deficient in DNA binding activate the p21 promoter to the same extent as wild type HNF4alpha1, indicating that direct DNA binding by HNF4alpha1 is not necessary for p21 activation. We also observed an in vitro and in vivo interaction between HNF4alpha1 and c-Myc, as well as a competition between these two transcription factors for interaction with promoter-bound Sp1 and regulation of p21. Finally, we show that c-Myc competes with HNF4alpha1 for control of apolipoprotein C3 (APOC3), a gene associated with the differentiated hepatic phenotype. These results suggest a general model by which a differentiation factor (HNF4alpha1) and a proliferation factor (c-Myc) may compete for control of genes involved in cell proliferation and differentiation. [Abstract/Link to Full Text]

Mukherjee A, Wilson EM, Rotwein P
IGF Binding Protein-5 Blocks Skeletal Muscle Differentiation by Inhibiting IGF Actions.
Mol Endocrinol. 2007 Sep 20;
Signaling through the IGF-I receptor by locally produced IGF-I or -II is critical for normal skeletal muscle development and repair after injury. In most tissues, IGF action is modulated by IGF binding proteins (IGFBPs). IGFBP-5 is produced by muscle cells, and previous studies have suggested that when over-expressed it may either facilitate or inhibit IGF actions, and thus potentially enhance or diminish IGF-mediated myoblast differentiation or survival. To resolve these contradictory observations and discern the mechanisms of action of IGFBP-5, we studied its effects in cultured muscle cells. Purified wild-type (WT) mouse IGFBP-5 or a variant with diminished extra-cellular matrix binding (C domain mutant) each prevented differentiation at final concentrations as low as 3.5 nM, while analogs with reduced IGF binding (N domain mutant) were ineffective even at 100 nM. None of the IGFBP-5 variants altered cell number. An IGF-I analog (R(3)IGF-I) with diminished affinity for IGFBPs promoted full muscle differentiation in the presence of IGFBP-5(WT), showing that IGFBP-5 interferes with IGF-dependent signaling pathways in myoblasts. When IGFBP-5(WT) or variants were overexpressed by adenovirus-mediated gene transfer, concentrations in muscle culture medium reached 500 nM, and differentiation was inhibited, even by IGFBP-5(N). As 200 nM of purified IGFBP-5(N) prevented activation of the IGF-I receptor by 10 nM IGF-II as effectively as 2 nM of IGFBP-5(WT), our results not only demonstrate that IGFBP-5 variants with reduced IGF binding affinity impair muscle differentiation by blocking IGF actions, but underscore the need for caution when labeling effects of IGFBPs as "IGF-independent", since even low-affinity analogues may potently inhibit IGF-I or -II if present at high enough concentrations in biological fluids. [Abstract/Link to Full Text]

Ceraudo E, Murail S, Tan YV, Lacap�re JJ, Neumann JM, Couvineau A, Laburthe M
The vasoactive intestinal peptide alpha helix up to C-terminus interacts with the N-terminal ectodomain of the human VPAC1 receptor : photoaffinity, molecular modeling and dynamics.
Mol Endocrinol. 2007 Sep 20;
The neuropeptide vasoactive intestinal peptide (VIP) strongly impacts on human pathophysiology and does so through interaction with class II G protein-coupled receptors. We characterized the C-terminus binding site of VIP in the N-terminal ectodomain (N-ted) of the human VPAC1 receptor: (i) The probe (125)I-[Bpa(28)]-VIP in which the C-terminal residue (Asn(28)) is substituted by a photoreactive para-benzoyl-L-Phe (Bpa) was used to photolabel the receptor. After receptor cleavage and Edman sequencing, it was shown that Asn(28) of VIP is in contact with Lys(127) in the receptor N-ted. Taking into account previous data, it follows that the C-terminal and central parts of VIP from Asn(28) to Phe(6) lie in the N-ted. (ii) A 3D model of the N-ted was constructed, the fold being identified as a Sushi domain with two antiparallel beta sheets and three disulfide bonds. The NMR structure of VIP was then docked into this model by taking into account the constraint provided by photoaffinity experiments with (125)I-[Bpa(28)]-VIP. It appeared that VIP runs parallel to the beta3-beta4 antiparallel sheets. (iii) We performed molecular dynamic simulations over 14 ns of the complex between VIP and receptor N-ted and the free N-ted. The structural model of the free N-ted is stable and VIP tends to further stabilize the N-ted structure more especially in the loops connecting the beta sheets. These structural studies provide a detailed molecular understanding of the VIP-receptor interaction. [Abstract/Link to Full Text]

Zhang Z, Li X, Lv W, Yang Y, Gao H, Yang J, Shen Y, Ning G
Ginsenoside Re Reduces Insulin Resistance through Inhibition of JNK and NF-{kappa}B.
Mol Endocrinol. 2007 Sep 20;
Ginsenoside Re(Re), a compound derived from Panax ginseng, shows an antidiabetic effect. However the molecular basis of its action remains unknown. We investigate insulin signaling, and anti-inflammation effect by Re in 3T3-L1 adipocytes and in high fat diet rats to dissect its anti-hyperglycemic mechanism. Glucose uptake is measured in 3T3-L1 cells and glucose infusion rate (GIR) determined by clamp in high fat diet (HFD) rats. The insulin signaling cascade, including IRbeta, IRS-1, PI3K, Akt and AS160, and Glut4 translocation are examined. Furthermore, JNK MAPK and NF-kappaB signaling cascade are also assessed. The results show Re increases glucose uptake in 3T3-L1 cells and GIR in HFD rats. The activation of insulin signaling by Re is initiated at IRS-1 and further passes on through PI-3K and downstream signaling cascade. Moreover, Re demonstrates an impressive suppression of JNK and NF-kappaB activation and IkappaBalpha degradation. In conclusion, Re reduces insulin resistance in 3T3-L1 adipocytes and HFD rats through inhibition of JNK and NF-kappaB activation. [Abstract/Link to Full Text]

Nishio SI, Kakizawa T, Chatelain G, Triqueneaux G, Brunet F, Rambaud J, Lamonerie T, Laudet V
OTX5 REGULATES PINEAL EXPRESSION OF THE ZEBRAFISH REV-ERB{alpha} THROUGH A NEW DNA BINDING SITE.
Mol Endocrinol. 2007 Sep 13;
The pineal gland plays a central role in the photoneuroendocrine system and acts as a photosensory organ in lower vertebrates. The orphan nuclear receptor Rev-erbalpha (NR1D1) has previously been shown to be expressed in the pineal and to be regulated with a robust circadian rhythm during zebrafish embryogenesis. This early pineal expression is under the control of the transcription factor Orthodenticle homeobox 5 (Otx5). In this paper, we show that Otx5 regulates the second zfRev-erbalpha promoter, ZfP2. Despite the absence of a classical Otx binding site within ZfP2 this regulation depends on the integrity of the Otx5 homeodomain. Mapping experiments as well as gel shift assays (EMSA) show that this interactions between Otx5 and ZfP2 depends on a non-canonical bipartite Otx binding site (GANNCTTA and TAAA) that we called Pineal Expression Related Element (PERE). We showed that PERE is necessary for pineal expression in vivo by injecting zebrafish embryos with wild type and mutated versions of zfRev-erbalpha promoter fused to GFP. Interestingly, PERE is found upstream of other genes expressed in the pineal gland suggesting that it may play an important role in governing pineal expression. Our data establish that PERE is a novel cis-acting element contributing to pineal-specific gene expression and to Otx target gene regulation. [Abstract/Link to Full Text]

Roizen JD, Asada M, Tong M, Tai HH, Muglia LJ
Preterm birth without progesterone withdrawal in 15-hydroxyprostaglandin dehydrogenase hypomorphic mice.
Mol Endocrinol. 2007 Sep 13;
Parturition is a complex mammalian physiological process whose fundamental determinants have remained elusive. The increasing incidence of human preterm birth, a leading cause of infant mortality, highlights the importance of further understanding mechanisms regulating the timing of birth. Parturition is initiated in most non-primate mammals, including mice, through a decrease in circulating progesterone caused by elevated prostaglandins. In humans, other higher primates and guinea pigs no consistent decrease in circulating progesterone occurs prior to the onset of labor. The divergence in endocrine control of labor initiation between most mammals compared to the great apes and guinea pigs gives rise to the question: how could a mechanism for the initiation of labor not requiring the withdrawal of progesterone evolve? Here, we genetically modulate prostaglandin signaling to determine the role of prostaglandin catabolism in the timing of birth. We find spontaneous preterm labor in the absence of progesterone withdrawal in 15-hydroxyprostaglandin dehydrogenase hypomorphic mice. The onset of labor in these hypomorphic mice is preceded by prematurely increased concentrations of prostaglandin E2 and F2alpha. Moreover, genetic crosses demonstrate a role for fetal genotype in birth timing. Together, these findings demonstrate a 15-hydroxyprostaglandin dehydrogenase-dependent shift in the physiology of murine parturition to one resembling the physiology of higher primates. Thus, endocrine control of labor has the capacity to plastically adapt to changes in genetically determined prostaglandin signals. [Abstract/Link to Full Text]

Kress E, Rezza A, Nadjar J, Samarut J, Plateroti M
The TR{alpha} gene encoding the thyroid hormone receptor TR{alpha}1 controls DNA-damage induced tissue repair.
Mol Endocrinol. 2007 Sep 13;
The thyroid hormone controls, via its nuclear receptor TRalpha1, intestinal crypt cell proliferation in the mouse. In order to understand whether this receptor also plays a role in intestinal regeneration after DNA damage, we applied a protocol of gamma-ray irradiation and monitored cell proliferation and apoptosis at several time points. In wild type mice, the dose of 8 Gray induced cell cycle arrest and apoptosis in intestinal crypts a few hours after irradiation. This phenomenon reverted 48h after irradiation. TRalpha(0/0) mutant mice displayed a constant low level of proliferating cells and a high apoptosis rate during the period of study. At the molecular level, in TRalpha(0/0) animals we observed a delay in the p53 phosphorylation induced by DNA damage. Looking for the expression of the protein-kinases responsible for p53 phosphorylation upon irradiation, we have focused on DNA-PKcs. The number of cells expressing DNA-PKcs in crypts remained high 48h after irradiation, specifically in TRalpha mutants. Altogether, in TRalpha(0/0) animals the rate of apoptosis in crypt cells remained high, apparently due to an elevated number of cells still presenting DNA damage. In conclusion, the TRalpha gene plays a role in crypt cell homeostasis by regulating the rate of cell renewal and apoptosis induced by DNA damage. [Abstract/Link to Full Text]

Angelova K, Fanelli F, Puett D
Contributions of Intracellular Loops 2 and 3 of the Lutropin Receptor in Gs Coupling.
Mol Endocrinol. 2007 Sep 13;
A number of amino acids essential for Gs coupling, i.e. hot spots, were identified following in vitro Ala-scanning mutagenesis of the cytosolic extensions of helices 3, 5, and 6 and of intracellular loops 2 and 3 of the human luteinizing hormone receptor (LHR). Consistent with the results of in vitro experiments involving ligand binding and ligand-mediated signaling in transiently transfected human embryonic kidney 293 cells, computational modeling of the isolated receptor and of the receptor-G protein complexes suggests an important role of the cytosolic extension of helix 3 and the N-terminal portion of the intracellular loop 2 in Gsalpha interaction, while the contribution of intracellular loop 3 is marginal. Mapping the hot spots into the computational models of LHR and the LHR-Gs complexes allowed for a distinction between receptor sites required for intramolecular structural changes (i.e. I460, T461, H466, and I549) and receptor sites more likely involved in G protein recognition (i.e. R464, T467, I468, Y470, Y550, and D564). The latter sites include the highly conserved arginine of the (E/D)R(Y/W) motif that is therefore likely to be a receptor recognition point for Gs rather than a switch of receptor activation. The results of in vitro and in silico experiments carried out in this study represent the first comprehensive delineation of functionality of the individual residues in the intracellular domains of LHR and establish potential switches of receptor activation as well as a map of the primary receptor recognition sites for Gs. A novel way to consider constitutively active mutants was inferred from this study, i.e. receptor states with improved complementarity for the G protein compared to the wild type receptor. [Abstract/Link to Full Text]

Dusell CD, Umetani M, Shaul PW, Mangelsdorf DJ, McDonnell DP
27-Hydroxycholesterol is an endogenous Selective Estrogen Receptor Modulator (SERM).
Mol Endocrinol. 2007 Sep 13;
Selective Estrogen Receptor Modulators (SERMs) are estrogen receptor (ER) ligands whose relative agonist/antagonist activities vary in a cell and promoter dependent manner. The molecular basis underlying this selectivity can be attributed to the ability of these ligands to induce distinct alterations in ER structure leading to differential recruitment of coactivators and corepressors. Whether SERM activity is restricted to synthetic ligands or if molecules exist in vivo that function in an analogous manner remains unsolved. However, the recent observation that oxysterols bind ER and antagonize the actions of 17beta-estradiol (E2) on the vascular wall suggests that this class of ligands possesses SERM activity. We demonstrate here that 27-hydroxycholesterol (27HC), the most prevalent oxysterol in circulation, functions as a SERM, the efficacy of which varies when assessed with different endpoints. Importantly, 27HC positively regulates both gene transcription and cell proliferation in cellular models of breast cancer. Using combinatorial peptide phage display we have determined that 27HC induces a unique conformational change in both ERalpha and ERbeta, distinguishing it from E2 and other SERMs. Thus, as with other ER ligands, it appears that the unique pharmacological activity of 27HC relates to its ability to impact ER structure and modulate cofactor recruitment. Cumulatively these data indicate that 27HC is an endogenous SERM with partial agonist activity in breast cancer cells and suggest that it may influence the pathology of breast cancer. Moreover, given the product-precursor relationship between 27HC and cholesterol, our findings have implications with respect to breast cancer risk in obese/hypercholesteremic individuals. [Abstract/Link to Full Text]

Dean T, Vilardaga JP, Potts JT, Gardella TJ
ALTERED SELECTIVITY OF PARATHYROID HORMONE (PTH) AND PTH-RELATED PROTEIN FOR DISTINCT CONFORMATIONS OF THE PTH/PTHrP RECEPTOR.
Mol Endocrinol. 2007 Sep 13;
Parathyroid Hormone (PTH) and PTH-related Protein (PTHrP) utilize the same G protein-coupled receptor - the PTH/PTHrP receptor or PTHR- to mediate their distinct biological actions. The extent to which the mechanisms by which the two ligands bind to the PTHR differ is unclear. We examined this question using several pharmacological and biophysical approaches. Kinetic dissociation and equilibrium binding assays revealed that the binding of (125)I-PTHrP(1-36) to the PTHR was more sensitive to GTPgammaS (added to functionally uncouple PTHR|b7G protein complexes) than was the binding of (125)I-PTH(1-34) ( approximately 75% maximum inhibition vs. approximately 20%). Fluorescence resonance energy transfer-based kinetic analyses revealed that PTHrP(1-36) bound to the PTHR more slowly, and dissociated from it more rapidly than did PTH(1-34). The cAMP signaling response capacity of PTHrP(1-36) in cells decayed more rapidly than did that of PTH(1-34) (t1/2 = approximately 1h vs. approximately 2h). Divergent residue five in the ligand: Ile in PTH and His in PTHrP, was identified as a key determinant of the altered receptor-interaction responses exhibited by the two peptides. We conclude that whereas PTH and PTHrP bind similarly to the G protein-coupled PTHR conformation (RG), PTH has a greater capacity to bind to the G protein-uncoupled conformation (R(0)), and hence, can produce cumulatively greater signaling responses (via R(0)-->RG isomerization), than can PTHrP. Such conformational selectivity may relate to the distinct modes by which PTH and PTHrP act biologically: endocrine vs. paracrine, and may help explain reported differences in the effects that the ligands have on calcium and bone metabolism when administered to humans. [Abstract/Link to Full Text]

Larance M, Ramm G, James DE
The GLUT4 Code.
Mol Endocrinol. 2007 Aug 23;
Despite being one of the first recognised targets of insulin action the acceleration of glucose transport into muscle and fat tissue remains one of the most enigmatic processes in the insulin action cascade. Glucose transport is accomplished by a shift in the distribution of the insulin-responsive glucose transporter GLUT4 from intracellular compartments to the plasma membrane in the presence of insulin. The complexity in deciphering the molecular blueprint of insulin regulation of glucose transport arises because it represents a convergence of two convoluted biological systems - vesicular transport and signal transduction. While more than 60 molecular players have been implicated in this orchestral performance it has been difficult to distinguish between mainly passive participants versus those that are clearly driving the process. The maze-like nature of the endosomal system makes it almost impossible to dissect the anatomical nature of what appears to be a medley of many overlapping and rapidly changing transitions. A major limitation is technology. It is clear that further progress in teasing apart the GLUT4 code will require the development and application of novel and advanced technologies that can discriminate one molecule from another in the living cell and to superimpose this upon a system in which the molecular environment can be carefully manipulated. Many are now taking on this challenge. [Abstract/Link to Full Text]

Dinapoli L, Capel B
SRY and the Standoff in Sex Determination.
Mol Endocrinol. 2007 Sep 20;
SRY was identified as the mammalian sex-determining gene more than 15 years ago and has been extensively studied since. Although many of the pathways regulating sexual differentiation have been elucidated, direct downstream targets of SRY are still unclear, making a 'top down' approach difficult. However, recent work has demonstrated that the fate of the gonad is actively contested by both male-promoting and female-promoting signals. Sox9 and Fgf9 push gonads towards testis differentiation. These two genes are opposed by Wnt4, and possibly RSPO1, which push gonads towards ovary differentiation. In this review, we will discuss the history of the field, current findings, and exciting new directions in vertebrate sex-determination. [Abstract/Link to Full Text]

Zhen Y, Krausz KW, Chen C, Idle JR, Gonzalez FJ
Metabolomic and genetic analysis of biomarkers for peroxisome proliferator-activated receptor alpha expression and activation.
Mol Endocrinol. 2007 Sep;21(9):
Peroxisome proliferator-activated receptor alpha (PPARalpha) is a nuclear receptor with manifold effects on intermediary metabolism. To define a set of urinary biomarkers that could be used to determine the efficacy of PPARalpha agonists, a metabolomic investigation was undertaken in wild-type and Pparalpha-null mice fed for 2 wk either a regular diet or a diet containing the PPARalpha ligand Wy-14,643 ([4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio] acetic acid), and their urine was analyzed by ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry. Principal components analysis of 6393 accurate mass positive ions revealed clustering as a single phenotype of the treated and untreated Pparalpha (-/-) mice plus two additional discrete phenotypes for the treated and untreated Pparalpha (+/+) mice. Biomarkers of PPARalpha activation were identified from their accurate masses and confirmed by tandem mass spectrometry of authentic compounds. Biomarkers were quantitated from raw chromatographic data using appropriate calibration curves. PPARalpha urinary biomarkers highly statistically significantly elevated by Wy-14,643 treatment included 11beta-hydroxy-3,20-dioxopregn-4-en-21-oic acid (>3700-fold), 11beta,20-dihydroxy-3-oxopregn-4-en-21-oic acid (50-fold), nicotinamide (>2-fold), nicotinamide 1-oxide (5-fold), 1-methylnicotinamide (1.5-fold), hippuric acid (2-fold), and 2,8-dihydroxyquinoline-beta-d-glucuronide (3-fold). PPARalpha urinary biomarkers highly statistically significantly attenuated by Wy-14,643 treatment included xanthurenic acid (1.3-fold), hexanoylglycine (20-fold), phenylpropionylglycine (4-fold), and cinnamoylglycine (9-fold). These biomarkers arise from PPARalpha effects on tryptophan, corticosterone, and fatty acid metabolism and on glucuronidation. This study underscores the power of mass spectrometry-based metabolomics combined with genetically modified mice in the definition of monogenic metabolic phenotypes. [Abstract/Link to Full Text]

Debevec D, Christian M, Morganstein D, Seth A, Herzog B, Parker M, White R
Receptor interacting protein 140 regulates expression of uncoupling protein 1 in adipocytes through specific peroxisome proliferator activated receptor isoforms and estrogen-related receptor alpha.
Mol Endocrinol. 2007 Jul;21(7):
Expression of uncoupling protein 1 (Ucp1) mRNA is elevated in differentiated adipocytes derived from brown or white adipose tissue devoid of the nuclear receptor corepressor receptor interacting protein 140 (RIP140). Increased expression is mediated in part by the recruitment of peroxisome proliferator activated receptors alpha and gamma, together with estrogen-related receptor alpha, which functions through a novel binding site on the Ucp1 enhancer. This demonstrates that regulation of Ucp1 expression in the absence of RIP140 involves derepression of at least three different nuclear receptors. The ability to increase expression of Ucp1 by beta-adrenergic signaling is independent of RIP140, as shown by the action of the beta(3)-adrenergic agonist CL 316,243 to stimulate expression in both brown and white adipocytes in the presence and absence of the corepressor. Therefore, the expression of this metabolic uncoupling protein in adipose cells is regulated by inhibition as well as activation of distinct signaling pathways. [Abstract/Link to Full Text]

Lee DY, Ianculescu I, Purcell D, Zhang X, Cheng X, Stallcup MR
Surface-scanning mutational analysis of protein arginine methyltransferase 1: roles of specific amino acids in methyltransferase substrate specificity, oligomerization, and coactivator function.
Mol Endocrinol. 2007 Jun;21(6):
Protein arginine methyltransferase 1 (PRMT1) is an arginine-specific protein methyltransferase that methylates a number of proteins involved in transcription and other aspects of RNA metabolism. Its role as a transcriptional coactivator for nuclear receptors involves its ability to bind to other coactivators, such as glucocorticoid receptor-interacting protein 1 (GRIP1), as well as its ability to methylate histone H4 and coactivators such as peroxisome proliferator-activated receptor gamma coactivator-1alpha. Its ability to form homodimers or higher-order homo-oligomers also is important for its methyltransferase activity. To understand the function of PRMT1 further, 19 surface residues were mutated, based on the crystal structure of PRMT1. Mutants were characterized for their ability to bind and methylate various substrates, form homodimers, bind GRIP1, and function as a coactivator for the androgen receptor in cooperation with GRIP1. We identified specific surface residues that are important for methylation substrate specificity and binding of substrates, for dimerization/oligomerization, and for coactivator function. This analysis also revealed functional relationships between the various activities of PRMT1. Mutants that did not dimerize well had poor methyltransferase activity and coactivator function. However, surprisingly, all dimerization mutants exhibited increased GRIP1 binding, suggesting that the essential PRMT1 coactivator function of binding to GRIP1 may require dissociation of PRMT1 dimers or oligomers. Three different mutants with altered substrate specificity had widely varying coactivator activity levels, suggesting that methylation of specific substrates is important for coactivator function. Finally, identification of several mutants that exhibited reduced coactivator function but appeared normal in all other activities tested, and finding one mutant with very little methyltransferase activity but normal coactivator function, suggested that these mutated surface residues may be involved in currently unknown protein-protein interactions that are important for coactivator function. [Abstract/Link to Full Text]

Maudsley S, Naor Z, Bonfil D, Davidson L, Karali D, Pawson AJ, Larder R, Pope C, Nelson N, Millar RP, Brown P
Proline-rich tyrosine kinase 2 mediates gonadotropin-releasing hormone signaling to a specific extracellularly regulated kinase-sensitive transcriptional locus in the luteinizing hormone beta-subunit gene.
Mol Endocrinol. 2007 May;21(5):
G protein-coupled receptor regulation of gene transcription primarily occurs through the phosphorylation of transcription factors by MAPKs. This requires transduction of an activating signal via scaffold proteins that can ultimately determine the outcome by binding signaling kinases and adapter proteins with effects on the target transcription factor and locus of activation. By investigating these mechanisms, we have elucidated how pituitary gonadotrope cells decode an input GnRH signal into coherent transcriptional output from the LH beta-subunit gene promoter. We show that GnRH activates c-Src and multiple members of the MAPK family, c-Jun NH2-terminal kinase 1/2, p38MAPK, and ERK1/2. Using dominant-negative point mutations and chemical inhibitors, we identified that calcium-dependent proline-rich tyrosine kinase 2 specifically acts as a scaffold for a focal adhesion/cytoskeleton-dependent complex comprised of c-Src, Grb2, and mSos that translocates an ERK-activating signal to the nucleus. The locus of action of ERK was specifically mapped to early growth response-1 (Egr-1) DNA binding sites within the LH beta-subunit gene proximal promoter, which was also activated by p38MAPK, but not c-Jun NH2-terminal kinase 1/2. Egr-1 was confirmed as the transcription factor target of ERK and p38MAPK by blockade of protein expression, transcriptional activity, and DNA binding. We have identified a novel GnRH-activated proline-rich tyrosine kinase 2-dependent ERK-mediated signal transduction pathway that specifically regulates Egr-1 activation of the LH beta-subunit proximal gene promoter, and thus provide insight into the molecular mechanisms required for differential regulation of gonadotropin gene expression. [Abstract/Link to Full Text]

Toumazou C, Li J, Wong J
Cofactor Restriction by Androgen Receptor N-terminal and C-terminal Interaction.
Mol Endocrinol. 2007 Jan 23;
Androgen receptor (AR) exerts its diverse biological functions primarily through its ability to regulate gene expression. As a member of nuclear receptor superfamily, AR recruits various coactivators to facilitate its transcriptional activity. The ligand-binding domains (LBD) of AR is believed to play a role in coactivator recruitment through a direct interaction between a hydrophobic coactivator binding groove in the LBD and a FXXLF or LXXLL motif within coactivators. In this study, we provide multiple lines of evidence showing that the FXXLF motif-containing ARA70 and ARA54 exhibit strong hormone-dependent interaction with the AR LBD but poorly with full-length AR. This drastic difference in interaction with ARA70 and ARA54 between the AR LBD and full-length AR is due to the hormone-dependent N-C interaction of AR. Like the AR LBD, full-length AR mutants defective in the N-C interaction exhibit strong hormone-dependent interaction with ARA70 and ARA54. Thus, our results suggest that in the full-length context the hydrophobic coactivator binding groove in the LBD is normally engaged in the liganded induced AR N-C interaction and thus restricted from interaction with other proteins. This finding raises fundamental question as to how AR recruits coactivators to regulate gene transcription. [Abstract/Link to Full Text]

Li J, Zhang D, Fu J, Huang Z, Wong J
Structural and Functional Analysis of Androgen Receptor in Chromatin.
Mol Endocrinol. 2007 Jan 16;
Androgen receptor (AR), a member of the nuclear receptor superfamily, is a modular protein comprised of a N-terminal domain (NTD), a central DNA binding domain (DBD) and a C-terminal ligand-binding domain (LBD). Previous structural and functional studies have shown that deletion of the LBD generates an AR molecule with full transcriptional activity in many transient transfection assays. In this study we show that deletion of either the NTD1-478 (ARDeltaN) or LBD680-919 (ARDeltaC) cripples AR transcriptional activity in chromatin. Both ARDeltaN and ARDeltaC mutants are impaired in binding to target genes in chromatin. Overexpression of SRC-1 coactivator partially rescued transcriptional and chromatin-binding defects of ARDeltaN and ARDeltaC mutants. Expression of SRC-1 also enhances the binding of the wild-type AR to chromatin, thus revealing a role of SRC-1 in promoting binding of AR to chromatin. We also demonstrate that expression of the AR NTD1-501 in trans can substantially rescue the chromatin binding, but not the transcriptional defect of ARDeltaN, indicating that binding of AR to chromatin is a step separable from AR induced transcriptional activation. Finally we present evidence that, in contrast to transient transfection, AR NTD alone cannot efficiently activate transcription in chromatin. [Abstract/Link to Full Text]

Recent Articles in BMC Endocrine Disorders

Linn T, Mann M, Mann M, Bretzel RG, Boedeker RH
Randomised prospective study for the effect of therapy on residual beta cell function in type-1 diabetes mellitus [ISRCTN70703138].
BMC Endocr Disord. 2003 Dec 10;3(1):5.
BACKGROUND: Newly diagnosed insulin-dependent diabetes mellitus is characterised by a temporary recovery of endogeneous insulin ("remission") after the beginning of medical treatment with subcutaneous insulin injections. Although most diabetologists think, that insulin reserve is related to reduced occurrence of diabetic long-term complications, such as eye, nerve and kidney disease, there is only one prospective controlled clinical study (the DCCT) addressing this question, however as secondary hypothesis. METHODS/DESIGN: Therefore, we composed a trial consisting of two cohorts with two therapeutic options within each cohort (conventional versus intensive therapy) and a three-year follow-up. In one group the patients are randomly assigned to the treatment regimes to test the statistical alternative hypothesis if variable insulin dosage is superior to fixed insulin injection in preserving insulin reserve measured by C-peptide in serum. Another group includes patients who prefer one of the two therapies, decline randomisation, but consent to follow-up. Apart from the determination of insulin reserve as a biological parameter a second primary endpoint was defined as 'therapeutic failure' according to the criteria of the European Association for the Study of Diabetes. Patients pass a training program to help them self-manage diabetes. A standardised protocol is being set up to minimize centre effects and bias of health care providers. Potential patient dependent bias will be investigated by questionnaires measuring psychic coping processes of people with diabetes. Management of visit dates is directly navigated by the database. Automated visit-reminders are mailed to patients and caregivers to optimise the number of visits on schedule. Data quality is regularly monitored and centres are informed on the results of continuous data management. [Abstract/Link to Full Text]

Shamshirsaz AA, Bekheirnia MR, Kamgar M, Pourzahedgilani N, Bouzari N, Habibzadeh M, Hashemi R, Shamshirsaz AA, Aghakhani S, Homayoun H, Larijani B
Metabolic and endocrinologic complications in beta-thalassemia major: a multicenter study in Tehran.
BMC Endocr Disord. 2003 Aug 12;3(1):4.
ABSTRACT : BACKGROUND : The combination of transfusion and chelation therapy has dramatically extended the life expectancy of thalassemic patients. The main objective of this study is to determine the prevalence of prominent thalassemia complications. METHODS : Two hundred twenty patients entered the study. Physicians collected demographic and anthropometric data and the history of therapies as well as menstrual histories. Patients have been examined to determine their pubertal status. Serum levels of 25(OH) D, calcium, phosphate, iPTH were measured. Thyroid function was assessed by T3, T4 and TSH. Zinc and copper in serum were determined by flame atomic absorption spectrophotometry. Bone mineral density (BMD) measurements at lumbar and femoral regions have been done using dual x-ray absorptiometry. The dietary calcium, zinc and copper intakes were estimated by food-frequency questionnaires. RESULTS : Short stature was seen in 39.3% of our patients. Hypogonadism was seen in 22.9% of boys and 12.2% of girls. Hypoparathyroidism and primary hypothyroidism was present in 7.6% and 7.7% of the patients. About 13 % of patients had more than one endocrine complication with mean serum ferritin of 1678 +/- 955 micrograms/lit. Prevalence of lumbar osteoporosis and osteopenia were 50.7% and 39.4%. Femoral osteoporosis and osteopenia were present in 10.8% and 36.9% of the patients. Lumbar BMD abnormalities were associated with duration of chelation therapy. Low serum zinc and copper was observed in 79.6% and 68% of the study population respectively. Serum zinc showed significant association with lumbar but not femoral BMD. In 37.2% of patients serum levels of 25(OH) D below 23 nmol/l were detected. CONCLUSION : High prevalence of complications among our thalassemics signifies the importance of more detailed studies along with therapeutic interventions. [Abstract/Link to Full Text]

Behme MT, Dupr� J, McDonald TJ
Glucagon-like peptide 1 improved glycemic control in type 1 diabetes.
BMC Endocr Disord. 2003 Apr 10;3(1):3.
BACKGROUND: Glucagon-like peptide-1 (GLP-1) and its agonists are under assessment in treatment of type 2 diabetes, by virtue of their antidiabetic actions, which include stimulation of insulin secretion, inhibition of glucagon release, and delay of gastric emptying. We examined the potential of GLP-1 to improve glycemic control in type 1 diabetes with no endogenous insulin secretion. METHODS: Dose-finding studies were carried out to establish mid range doses for delay of gastric emptying indicated by postponement of pancreatic polypeptide responses after meals. The selected dose of 0.63 micrograms/kg GLP-1 was administered before breakfast and lunch in 8-hour studies in hospital to establish the efficacy and safety of GLP-1. In outside-hospital studies, GLP-1 or vehicle was self-administered double-blind before meals with usual insulin for five consecutive days by five males and three females with well-controlled C-peptide-negative type 1 diabetes. Capillary blood glucose values were self-monitored before meals, at 30 and 60 min after breakfast and supper, and at bedtime. Breakfast tests with GLP-1 were conducted on the day before and on the day after 5-day studies. Paired t-tests and ANOVA were used for statistical analysis. RESULTS: In 8-hour studies time-averaged incremental (delta) areas under the curves(AUC) for plasma glucose through 8 hours were decreased by GLP-1 compared to vehicle (3.2 PlusMinus; 0.9, mean PlusMinus; se, vs 5.4 PlusMinus; 0.8 mmol/l, p <.05), and for pancreatic polypeptide, an indicator of gastric emptying, through 30 min after meals (4.0 PlusMinus; 3.1 vs 37 PlusMinus; 9.6 pmol/l, p <.05) with no adverse effects. Incremental glucagon levels through 60 min after meals were depressed by GLP-1 compared to vehicle (-3.7 PlusMinus; 2.5 vs 3.1 PlusMinus; 1.9 ng/l, p <.04). In 5-day studies, AUC for capillary blood glucose levels were lower with GLP-1 than with vehicle (-0.64 PlusMinus; 0.33 vs 0.34 PlusMinus; 0.26 mmol/l, p <.05). No assisted episode of hypoglycaemia or change in insulin dosage occurred. Breakfast tests on the days immediately before and after 5-day trials showed no change in the effects of GLP-1. CONCLUSION: We have demonstrated that subcutaneous GLP-1 can improve glucose control in type 1 diabetes without adverse effects when self-administered before meals with usual insulin during established intensive insulin treatment programs. [Abstract/Link to Full Text]

Abbott KC, Bernet VJ, Agodoa LY, Yuan CM
Diabetic ketoacidosis and hyperglycemic hyperosmolar syndrome after renal transplantation in the United States.
BMC Endocr Disord. 2003 Mar 24;3(1):1.
BACKGROUND: The incidence and risk factors for diabetic ketoacidosis (diabetic ketoacidosis) and hyperglycemic hyperosmolar syndrome (hyperglycemic hyperosmolar syndrome, previously called non-ketotic hyperosmolar coma) have not been reported in a national population of renal transplant (renal transplantation) recipients. METHODS: We performed a historical cohort study of 39,628 renal transplantation recipients in the United States Renal Data System between 1 July 1994 and 30 June 1998, followed until 31 Dec 1999. Outcomes were hospitalizations for a primary diagnosis of diabetic ketoacidosis (ICD-9 code 250.1x) and hyperglycemic hyperosmolar syndrome (code 250.2x). Cox Regression analysis was used to calculate adjusted hazard ratios for time to hospitalization for diabetic ketoacidosis or hyperglycemic hyperosmolar syndrome. RESULTS: The incidence of diabetic ketoacidosis and hyperglycemic hyperosmolar syndrome were 33.2/1000 person years (PY) and 2.7/1000 PY respectively for recipients with a prior diagnosis of diabetes mellitus (DM), and 2.0/1000 PY and 1.1/1000 PY in patients without DM. In Cox Regression analysis, African Americans (AHR, 2.71, 95 %CI, 1.96-3.75), females, recipients of cadaver kidneys, patients age 33-44 (vs. >55), more recent year of transplant, and patients with maintenance TAC (tacrolimus, vs. cyclosporine) had significantly higher risk of diabetic ketoacidosis. However, the rate of diabetic ketoacidosis decreased more over time in TAC users than overall. Risk factors for hyperglycemic hyperosmolar syndrome were similar except for the significance of positive recipient hepatitis C serology and non-significance of female gender. Both diabetic ketoacidosis (AHR, 2.44, 95% CI, 2.10-2.85, p < 0.0001) and hyperglycemic hyperosmolar syndrome (AHR 1.87, 95% CI, 1.22-2.88, p = 0.004) were independently associated with increased mortality. CONCLUSIONS: We conclude that diabetic ketoacidosis and hyperglycemic hyperosmolar syndrome were associated with increased risk of mortality and were not uncommon after renal transplantation. High-risk groups were identified. [Abstract/Link to Full Text]

Borelli MI, Rubio M, Garc�a ME, Flores LE, Gagliardino JJ
Tyrosine hydroxylase activity in the endocrine pancreas: changes induced by short-term dietary manipulation.
BMC Endocr Disord. 2003 Mar 24;3(1):2.
BACKGROUND: Tyrosine hydroxylase (TH) activity and its possible participation in the control of insulin secretion were studied in pancreatic islets of adult Wistar rats fed a standard commercial diet (SD) or carbohydrates alone (CHD) for one week. TH activity, norepinephrine (NE) content, and glucose-induced insulin secretion were assessed. Blood glucose and insulin levels were measured at the time of sacrifice. RESULTS: CHD rats had significantly higher blood glucose and lower insulin levels than SD rats (114.5 PlusMinus; 6.7 vs 80.7 PlusMinus; 7.25 mg/dl, p < 0.001; 20.25 PlusMinus; 2.45 vs 42.5 PlusMinus; 4.99 &mgr;U/ml, p < 0.01, respectively). Whereas TH activity was significantly higher in CHD isolated islets (600 PlusMinus; 60 vs 330 PlusMinus; 40 pmol/mg protein/h; p < 0.001), NE content was significantly lower (18 PlusMinus; 1 vs 31 PlusMinus; 5 pmol/mg protein), suggesting that TH activity would be inhibited by the end-products of catecholamines (CAs) biosynthetic pathway. A similar TH activity was found in control and solarectomized rats (330 PlusMinus; 40 vs 300 PlusMinus; 80 pmol/mg protein/h), suggesting an endogenous rather than a neural origin of TH activity. CHD islets released significantly less insulin in response to glucose than SD islets (7.4 PlusMinus; 0.9 vs 11.4 PlusMinus; 1.1 ng/islet/h; p < 0.02). CONCLUSIONS: TH activity is present in islet cells; dietary manipulation simultaneously induces an increase in this activity together with a decrease in glucose-induced insulin secretion in rat islets. TH activity - and the consequent endogenous CAs turnover - would participate in the paracrine control of insulin secretion. [Abstract/Link to Full Text]

Larijani B, Pajouhi M, Ghanaati H, Bastanhagh MH, Abbasvandi F, Firooznia K, Shirzad M, Amini MR, Sarai M, Abbasvandi N, Baradar-Jalili R
Treatment of hyperfunctioning thyroid nodules by percutaneous ethanol injection.
BMC Endocr Disord. 2002 Dec 6;2(1):3.
BACKGROUND: Autonomous thyroid nodules can be treated by a variety of methods. We assessed the efficacy of percutaneous ethanol injection in treating autonomous thyroid nodules. METHODS: 35 patients diagnosed by technetium-99 scanning with hyperfunctioning nodules and suppressed sensitive TSH (sTSH) were given sterile ethanol injections under ultrasound guidance. 29 patients had clinical and biochemical hyperthyroidism. The other 6 had sub-clinical hyperthyroidism with suppressed sTSH levels (<0.24 &mgr;IU/ml) and normal thyroid hormone levels. Ethanol injections were performed once every 1-4 weeks. Ethanol injections were stopped when serum T3, T4 and sTSH levels had returned to normal, or else injections could no longer be performed because significant side effects. Patients were followed up at 3, 6 and, in 15 patients, 24 months after the last injection. RESULTS: Average pre-treatment nodule volume [18.2 PlusMinus; 12.7 ml] decreased to 5.7 PlusMinus; 4.6 ml at 6 months follow-up [P < 0.001]. All patients had normal thyroid hormone levels at 3 and 6 months follow-up [P < 0.001 relative to baseline]. sTSH levels increased from 0.09 PlusMinus; 0.02 &mgr;IU/ml to 0.65 PlusMinus; 0.8 &mgr;IU/ml at the end of therapy [P < 0.05]. Only 3 patients had persistent sTSH suppression at 6 months post-therapy. T4 and sTSH did not change significantly between 6 months and 2 years [P > 0.05]. Ethanol injections were well tolerated by the patients, with only 2 cases of transient dysphonia. CONCLUSION: Our findings indicate that ethanol injection is an alternative to surgery or radioactive iodine in the treatment of autonomous thyroid nodules. [Abstract/Link to Full Text]

Tyrberg B, Anachkov KA, Dib SA, Wang-Rodriguez J, Yoon KH, Levine F
Islet expression of the DNA repair enzyme 8-oxoguanosine DNA glycosylase (Ogg1) in human type 2 diabetes.
BMC Endocr Disord. 2002 Apr 25;2(1):2.
BACKGROUND: It has become increasingly clear that beta-cell failure plays a critical role in the pathogenesis of type 2 diabetes. Free-radical mediated beta-cell damage has been intensively studied in type 1 diabetes, but not in human type 2 diabetes. Therefore, we studied the protein expression of the DNA repair enzyme Ogg1 in pancreases from type 2 diabetics. Ogg1 was studied because it is the major enzyme involved in repairing 7,8-dihydro-8-oxoguanosine DNA adducts, a lesion previously observed in a rat model of type 2 diabetes. Moreover, in a gene expression screen, Ogg1 was over-expressed in islets from a human type 2 diabetic. METHODS: Immunofluorescent staining of Ogg1 was performed on pancreatic specimens from healthy controls and patients with diabetes for 2-23 years. The intensity and islet area stained for Ogg1 was evaluated by semi-quantitative scoring. RESULTS: Both the intensity and the area of islet Ogg1 staining were significantly increased in islets from the type 2 diabetic subjects compared to the healthy controls. A correlation between increased Ogg1 fluorescent staining intensity and duration of diabetes was also found. Most of the staining observed was cytoplasmic, suggesting that mitochondrial Ogg1 accounts primarily for the increased Ogg1 expression. CONCLUSION: We conclude that oxidative stress related DNA damage may be a novel important factor in the pathogenesis of human type 2 diabetes. An increase of Ogg1 in islet cell mitochondria is consistent with a model in which hyperglycemia and consequent increased beta-cell oxidative metabolism lead to DNA damage and the induction of Ogg1 expression. [Abstract/Link to Full Text]

Parappil A, Doi SA, Al-Shoumer KA
Diagnostic criteria for diabetes revisited: making use of combined criteria.
BMC Endocr Disord. 2002;2(1):1.
BACKGROUND: Existing cut-offs for fasting plasma glucose (FPG) and post-load glucose (2hPG) criteria are not equivalent in the diagnosis of diabetes and glucose intolerance. Adjusting cut-offs of single measurements have not helped so we undertook this project to see if they could be complementary. METHODS: We performed oral glucose tolerance tests and mean levels of hemoglobin A1c (HbA1c) measurements on 43 patients referred to a diabetes clinic for possible diabetes. Results of single and combined use of the FPG and 2hPG criteria were evaluated against the levels of HbA1c and results re-interpreted in the light of existing reports in the literature. RESULTS: Our results confirm that the FPG and the 2hPG, being specific and sensitive respectively for the presence of glucose intolerance or diabetes, are not equivalent. They are shown to be indeed complementary and a re-definition of diagnostic criteria based on their combined use is proposed. CONCLUSIONS: We conclude that altering single measurement cut-offs for the diagnosis of diabetes and altered glucose tolerance will not result in better outcomes. We present the case for a combined criteria in the diagnosis and definition of diabetes with a FPG>/=7 mmol/L AND 2-hour glucose >/=7.8 mmol/L being used to define diabetes while a FPG<7 mmol/L AND 2-hour glucose <7.8 mmol/L being used to define normality. Discordant values will define impaired glucose tolerance (IGT). This proposal requires prospective evaluation in a large cohort. [Abstract/Link to Full Text]

Borelli MI, Gagliardino JJ
Possible modulatory effect of endogenous islet catecholamines on insulin secretion.
BMC Endocr Disord. 2001;1(1):1.
BACKGROUND: The possible participation of endogenous islet catecholamines (CAs) in the control of insulin secretion was tested. METHODS: Glucose-induced insulin secretion was measured in the presence of 3-Iodo-L-Tyrosine (MIT), a specific inhibitor of tyrosine-hydroxylase activity, in fresh and precultured islets isolated from normal rats. Incubated islets were also used to measure CAs release in the presence of low and high glucose, and the effect of alpha2-(yohimbine [Y] and idazoxan [I]) and alpha1-adrenergic antagonists (prazosin [P] and terazosin [T]) upon insulin secretion elicited by high glucose. RESULTS: Fresh islets incubated with 16.7 mM glucose released significantly more insulin in the presence of 1 &mgr;M MIT (6.66 +/- 0.39 vs 5.01 +/- 0.43 ng/islet/h, p < 0.02), but did not affect significantly the insulin response to low glucose. A similar enhancing effect of MIT upon insulin secretion was obtained using precultured islets devoid of neural cells, but absolute values were lower than those from fresh islets, suggesting that MIT inhibits islet rather than neural tyrosine hydroxylase. CAs concentration in the incubation media of fresh isolated islets was significantly higher in the presence of 16.7 than 3.3 mM glucose: dopamine 1.67 +/- 0.13 vs 0.69 +/- 0.13 pg/islet/h, p < 0.001, and noradrenaline 1.25 +/- 0.17 vs 0.49 +/- 0.04 pg/islet/h, p < 0.02. Y and I enhanced the release of insulin elicited by 16.7 mM glucose while P and T decreased such secretion. CONCLUSION: Our results suggest that islet-originated CAs directly modulate insulin release in a paracrine manner. [Abstract/Link to Full Text]

Recent Articles in Endocrine Journal

Nomura T, Ikeda Y, Nakao S, Ito K, Ishida K, Suehiro T, Hashimoto K
Muscle Strength is a Marker of Insulin Resistance in Patients with Type 2 Diabetes: A Pilot Study.
Endocr J. 2007 Sep 25;
To examine the effect of muscle strength on insulin resistance, we investigated the association between quantitative lower-extremity muscle strength and insulin resistance index as evaluated by homeostasis model assessment (HOMA-IR) in patients with type 2 diabetes (20 men and 20 women, mean age +/- SD: 53.3 +/- 12.7 years). By simple linear regression analyses, the knee extension force normalized for body weight (%KEF) was found to be significantly correlated with HOMA-IR in both male (r = -0.510, P < 0.05) and female patients (r = -0.462, P < 0.05). Stepwise regression analysis also showed that %KEF was an independent determinant of HOMA-IR (beta = -0.331, F = 5.400, P < 0.005), as was BMI (beta = 0.409, F = 8.260, P < 0.05). Our data suggest that lower-extremity muscle strength is independently associated with insulin resistance, which seems to be consistent with previous reports that resistance training improves glycemic control in type 2 diabetic patients. Further studies based on a larger study population will be required to confirm this possibility. [Abstract/Link to Full Text]

Ohmura C, Watada H, Shimizu T, Sakai K, Uchino H, Fujitani Y, Kanazawa A, Hirose T, Kawamori R
Calcium Channel Blocker, Azelnidipine, Reduces Lipid Hydroperoxides in Patients with Type 2 Diabetes Independent of Blood Pressure.
Endocr J. 2007 Sep 25;
Anti-hypertensive agents with antioxidative effects are potentially useful for diabetic patients with hypertension to prevent the onset and progression of their complication. While dihydropyridine-type calcium antagonists are among the frequently used anti-hypertensive drugs, azelnidipine, a novel calcium antagonist, has been reported to have a unique anti-oxidative effect in vitro and in animals. In this study, we measured lipid hydroperoxides in human sample using diphenyl-1-pyrenylphosphine for the first time, and used the value of lipid hydroperoxides as an index of oxidative stress. Then, we compared the antioxidative properties of azelnidipine and amlodipine, a frequently used calcium antagonist in hypertensive diabetic patients. Administration of vitamin C and E for 8 weeks significantly reduced lipid hydroperoxides in erythrocyte membrane in normal subjects. In hypertensive diabetic patients, azelnidipine treatment for 12 weeks induced a more significant fall in erythrocyte lipid hydroperoxide level than amlodipine, though blood pressure during each treatment was comparable. Our data confirm the usefulness of lipid hydroperoxides in erythrocyte membrane as a marker of oxidative stress in vivo, and indicate that azelnidipine has a unique antioxidative property in human. [Abstract/Link to Full Text]

Ashawesh K, Abdulqawi R, Redford D, Barton D
Postmenopausal hyperandrogenism of ovarian origin: diagnostic and therapeutic difficulties.
Endocr J. 2007 Sep;54(4):647. [Abstract/Link to Full Text]

Uzunlulu M, Oguz A
Is Metabolic Syndrome a Condition Independent of Prediabetes and Type 2 Diabetes Mellitus? A Report from Turkey.
Endocr J. 2007 Sep 14;
It has been suggested that metabolic syndrome (MetS) overlaps prediabetes and type 2 diabetes and that it is not necessary to consider it as a separate clinical entity. In the present study, patients with normoglycemia and dysglycemia were compared in terms of MetS frequency and MetS criteria characteristics, in order to test the appropriateness of considering MetS as a condition independent of prediabetes and type 2 diabetes. A total of 1222 (801 females, 401 males, mean age: 51.50 +/- 11.73 y) consecutive patients attending Internal Medicine outpatient clinics were included. Cases were assigned into two groups: patients with normoglycemia (fasting plasma glucose < 100 mg/dl, n = 555) or dysglycemia (fasting plasma glucose >/= 100 mg/dl and/or receiving antidiabetic treatment, n = 667). Groups were compared in terms of MetS frequency and MetS criteria characteristics. A 2-hour oral glucose tolerance test was administered to the normoglycemia group. In addition, patients with MetS were assigned into two groups: patients with normoglycemia and dysglycemia. These two groups were also compared in terms of MetS criteria characteristics. Adult Treatment Panel III criteria were used for the diagnosis of MetS. The overall frequency of MetS was 52.2%. MetS was found in 72.7% of patients with dysglycemia and 27.6% of patients with normoglycemia (p = 0.001). Mean systolic and diastolic blood pressure, waist circumference and triglyceride levels were similar between normoglycemic and dysglycemic MetS patients (p > 0.05). Impaired glucose tolerance was higher among normoglycemic MetS patients compared to normoglycemic patients without MetS (13.7% vs. 6.5%, p = 0.006). In conclusion, although MetS is a well known risk factor for type 2 diabetes, our results support that it is a separate entity independent of prediabetes and type 2 diabetes mellitus. [Abstract/Link to Full Text]

Kimura R, Imaeda K, Mizuno T, Wakami K, Yamada K, Okayama N, Kamiya Y, Joh T
Severe Ascites with Hypothyroidism and Elevated CA125 Concentration: A Case Report.
Endocr J. 2007 Sep 14;
Ascites caused by hypothyroidism is rare and the pathogenesis is unclear. Several reports have presented cases of progressive ascites with hypothyroidism and elevated tumor markers. We report a 31-year-old female case with massive ascites and elevated serum CA 125 concentrations. The patient had no typical feature of hypothyroidism except an accumulation of ascitic fluid which showed elevated total protein concentration and a high serum-ascites albumin gradient (SAAG). There was no finding of malignancy. Following thyroid hormone replacement, the ascites was completely resolved accompanied by reduced concentrations of serum CA125. In general, primary hypothyroidism with ascites presents with coexisting massive pericardial or pleural effusion. The massive ascites and increased serum CA125 concentrations may have led us to make the incorrect diagnosis of ovarian malignancy. The evaluation of thyroid function is useful to determine the pathology of high-protein ascites or elevated tumor markers, and ascites may be treatable by thyroid replacement therapy. [Abstract/Link to Full Text]

Ano S, Satoh H, Ishikawa S, Nakazawa K, Hizawa N
Bilateral Adrenal Metastasis from Lung Adenocarcinoma.
Endocr J. 2007 Sep 14; [Abstract/Link to Full Text]

Tsuchida K, Nakatani M, Uezumi A, Murakami T, Cui X
Signal Transduction Pathway through Activin Receptors as a Therapeutic Target of Musculoskeletal Diseases and Cancer.
Endocr J. 2007 Sep 14;
Activin, myostatin and other members of the TGF-ss superfamily signal through a combination of type II and type I receptors, both of which are transmembrane serine/threonine kinases. Activin type II receptors, ActRIIA and ActRIIB, are primary ligand binding receptors for activins, nodal, myostatin and GDF11. ActRIIs also bind a subset of bone morphogenetic proteins (BMPs). Type I receptors that form complexes with ActRIIs are dependent on ligands. In the case of activins and nodal, activin receptor-like kinases 4 and 7 (ALK4 and ALK7) are the authentic type I receptors. Myostatin and GDF11 utilize ALK5, although ALK4 could also be activated by these growth factors. ALK4, 5 and 7 are structurally and functionally similar and activate receptor-regulated Smads for TGF-ss, Smad2 and 3. BMPs signal through a combination of three type II receptors, BMPRII, ActRIIA, and ActRIIB and three type I receptors, ALK2, 3, and 6. BMPs activate BMP-specific Smads, Smad1, 5 and 8. Smad proteins undergo multimerization with co-mediator Smad, Smad4, and translocated into the nucleus to regulate the transcription of target genes in cooperation with nuclear cofactors. The signal transduction pathway through activin type II receptors, ActRIIA and ActRIIB, with type I receptors is involved in various human diseases. In this review, we discuss the role of signaling through activin receptors as therapeutic targets of intractable neuromuscular diseases, endocrine disorders and cancers. [Abstract/Link to Full Text]

Fukumoto S
Actions and Mode of Actions of FGF19 Subfamily Members.
Endocr J. 2007 Sep 14;
Fibroblast growth factors (FGFs) are humoral factors with diverse biological functions. While most FGFs were shown to work as local factors regulating cell growth and differentiation, recent investigations indicated that FGF19 subfamily members, FGF15/19, FGF21 and FGF23 work as systemic factors. FGF15/19 produced by intestine inhibits bile acid synthesis and FGF21 from liver is involved in carbohydrate and lipid metabolism. In addition, FGF23 was shown to be produced by bone and regulate phosphate and vitamin D metabolism. Furthermore, these FGFs require klotho or betaklotho for their actions in addition to canonical FGF receptors. It is possible that these FGFs together with their receptor systems might be targets for novel therapeutic measures in the future. [Abstract/Link to Full Text]

Fujimoto K, Sasaki T, Hiki Y, Nemoto M, Utsunomiya Y, Yokoo T, Nakai N, Ohashi T, Hosoya T, Eto Y, Tajima N
In vitro and Pathological Investigations of MODY5 with the R276X-HNF1beta (Tcf2) Mutation.
Endocr J. 2007 Sep 18;
Maturity-onset diabetes of the young type 5 (MODY5) is caused by mutation of hepatocyte nuclear factor 1beta (HNF1beta) (Tcf2) gene, resulting in a wide range of phenotypes including diabetes and renal abnormalities, but little is known about the pathogenesis of the clinical spectrum. We describe a 27-year-old Japanese male with a MODY phenotype including an atrophic kidney and multiple renal cysts. Genetic analysis revealed the patient to be heterozygous for a nonsense mutation in codon 276 of the HNF1beta gene (CGA or Arginine to TGA or stop codon; R276X). To clarify the pathophysiological relevance of this mutation, we conducted an in vitro study monitoring human C-peptide secretion after transfecting both the HNF1beta mutant cDNA and preproinsulin cDNA into a murine beta cell line, MIN6. Functional studies of the transformed MIN6 cells indicated that expression of the R276X caused a significant decrease in glucose-stimulated insulin secretion but no change in either KCl-stimulated or basal insulin secretion. These results suggest that the R276X functions in a negative manner in regard to metabolic responses of insulin secretion in beta cells. Analysis with light and electron microscopy on biopsied kidney specimens suggested that the origin of the cysts might be glomeruli but the primary lesion could be tubules. [Abstract/Link to Full Text]

Oki K, Yamane K, Yoneda M, Nojima H, Watanabe H, Kohno N
A Case of Addison's Disease Confirmed with Low Dose Cosyntropin Stimulation Test.
Endocr J. 2007 Sep 18;
An eighty-year-old man who had complained of skin pigmentation and weight loss was referred to our hospital. Upon physical examination, marked hyperpigmentation was found on the whole body including oral mucosa, tongue and fingernails. Endocrinological findings showed increased ACTH (126 pg/ml) and normal serum cortisol (15.4 mug/dl). First, we used a 250 mug cosyntropin stimulation test which is valid to diagnose Addison's disease, resulting in an adequate cortisol response. Second, we performed 1 mug cosyntropin stimulation test, and the cortisol response was blunted. Since the diagnosis of Addison's disease was fairly certain, he was treated with hydrocortisone 15 mg/day, and improvement of his skin pigmentation and an increase in body weight were observed. To our knowledge, this is the first report that 1 mug cosyntropin stimulation test was helpful to make diagnosis as having Addison's disease rather than the 250 mug cosyntropin stimulation test, although it is established that the 1 mug cosyntropin stimulation test is useful in secondary or relative adrenal insufficiency. [Abstract/Link to Full Text]

Sakane N, Kotani K, Hioki C, Yoshida T, Kawada T
Up-Regulation of Muscle Uncoupling Protein 3 gene Expression by Calcium Channel Blocker, Benidipine Hydrochloride in Rats.
Endocr J. 2007 Sep 18;
To examine whether benidipine hydrochloride, one of the calcium channel blockers, up-regulate uncoupling protein 3 (UCP3) expression in two skeletal muscles (gastrocnemius and soleus) in rats. Wistar rats were treated orally with benidipine hydrochloride at 4 mg/kg for 7 days. Blood pressure was measured after 4 days. At the end of experiments, the rats were weighed, and brown adipose tissue (BAT) and skeletal muscles (gastrocnemius and soleus muscles) were removed. The mRNA levels of uncoupling protein 1 (UCP1) and UCP3 were measured using the real-time quantitative reverse transcription-polymerase chain reaction method. Benidipine reduced body weight and also had a hypotensive effect. In rats treated with benidipine, UCP1 mRNA levels were significantly increased 1.4-fold in BAT, and UCP3 mRNA levels in BAT and gastrocnemius muscle were significantly increased 1.7 and 3.0-fold, respectively, compared with the control rats. There was no difference in UCP3 mRNA levels in soleus muscle between the two groups. We concluded that benidipine up-regulates not only UCP1 gene expression in BAT but also UCP3 gene expression in BAT and gastrocnemius muscle, which may contribute to thermogenesis in rats. [Abstract/Link to Full Text]

Sato H, Koike Y, Honma M, Yagame M, Ito K
Evaluation of Thyroid Hormone Action in a Case of Generalized Resistance to Thyroid Hormone with Chronic Thyroiditis: Discovery of a Novel Heterozygous Missense Mutation (G347A).
Endocr J. 2007 Sep 7;
Resistance to thyroid hormone (RTH) is a dominantly inherited syndrome of variable tissue hyporesponsiveness to thyroid hormone (TH). Its characteristics are a high level of TH and inappropriate lack of TSH suppression. RTH is mainly categorized as generalized RTH (GRTH), pituitary RTH (PRTH), and peripheral tissue RTH (PTRTH). Untreated subjects with GRTH usually achieve a normal metabolic state. We describe a 21-year-old Japanese woman with GRTH and coincidental chronic thyroiditis. Physical examination revealed palpable goiter, congenital alopecia on top of the head, and short stature. She showed elevated levels of free triiodothyronine (FT3) and free thyroxine (FT4), and an inappropriately normal level of TSH. Anti-thyroglobulin and anti-thyroid peroxidase antibodies were positive. A TRH stimulation test showed a normal TSH response. The patient received the standardized diagnostic protocol, administration of incremental doses of liothyronine (L-T3). The peak TSH level after the TRH stimulation test gradually decreased. The patient showed low sensitivity to TH in terms of bone metabolism, protein catabolism, lipid metabolism, and urine magnesium metabolism. Sequence analysis of the TR beta gene was performed with informed consent, and this revealed a novel heterozygous mutation at codon 347 resulting in a GGG (glycine) to GCG (alanine) substitution (G347A). The patient was diagnosed as having GRTH with chronic thyroiditis, and carrying a novel mutation, G347A, of the TR beta gene. [Abstract/Link to Full Text]

Choi YO, Park JH, Song YS, Lee W, Moriyama Y, Choe H, Leem CH, Jang YJ
Involvement of Vesicular H(+)-ATPase in Insulin-Stimulated Glucose Transport in 3T3-F442A Adipocytes.
Endocr J. 2007 Sep 7;
In secretory cells, osmotic swelling of secretory granules is proposed to be an intermediate step in exocytic fusion of the granules with the plasma membrane. For osmotic swelling of the granule, a H(+) gradient generated by vacuolar-type H(+)-ATPase (V-ATPase) may be a driving force for accumulation of K(+) via its exchange with H(+), concurrent with accumulation of Cl(-) and H(2)O. Here, we investigated whether a similar chemiosmotic mechanism is involved in the insulin-stimulated recruitment of GLUT4 to the plasma membrane in 3T3-F442A adipocytes. Incubating cells in a hypo-osmotic medium significantly increased 2-deoxy glucose (2-DG) uptake and the plasma membrane GLUT4 content (possibly via induction of osmotic swelling of GLUT4-containing vesicles (G4V)) and also potentiated the insulin-stimulated 2-DG uptake. Promotion of the G4V membrane ionic permeability using nigericin, an electroneutral K(+)/H (+) exchange ionophore, increased 2-DG uptake and the plasma membrane GLUT4 content. However, co-treatment with nigericin and insulin did not show an additive effect. Bafilomycin A(1), a diagnostically specific inhibitor of V-ATPase, inhibited insulin-and nigericin-stimulated 2-DG uptake. Immunoadsorption plus immunoblott -ing demonstrated that GLUT4 and V-ATPase co-localize in the same intracellular membranes. Together, these results indicate that V-ATPases in the G4V membrane may play an important role in the insulin-stimulated exocytic fusion of G4V with the plasma membrane via its participation in osmotic swelling of the vesicle. [Abstract/Link to Full Text]

Ueta Y, Hashimoto H, Onuma E, Takuwa Y, Ogata E
Hypothalamic Neuropeptides and Appetite Response in Anorexia-Cachexia Animal.
Endocr J. 2007 Sep 7; [Abstract/Link to Full Text]

Maeshima A, Miya M, Mishima K, Yamashita S, Kojima I, Nojima Y
Activin A: Autocrine Regulator of Kidney Development and Repair.
Endocr J. 2007 Sep 7; [Abstract/Link to Full Text]

Kurokawa A, Azuma K, Mita T, Toyofuku Y, Fujitani Y, Hirose T, Iwabuchi K, Ogawa H, Takeda S, Kawamori R, Watada H
2-Methoxyestradiol Reduces Monocyte Adhesion to Aortic Endothelial Cells in Ovariectomized Rats.
Endocr J. 2007 Sep 8;
2-Methoxyestradiol (2-ME) is an endogenous metabolite of estradiol with no affinity for estrogen receptors. It inhibits cell proliferation, thus is a potentially useful drug to block the progression of atherosclerosis. As a first step to examining the anti-atherosclerotic effects of 2-ME, we investigated monocyte adhesion to aortic endothelial cells, which is considered a prerequisite to atherosclerosis in vivo. Eight-week-old Sprague-Dawley rats were ovariectomized then treated by slow-release pellets with placebo, 17-beta-estradiol (5 mug/day), low-dose 2-ME (10 mug/day), or high-dose 2-ME (100 mug/day). After 6 weeks, enface analysis showed an increased number of monocytes adhering to endothelial cells of the thoracic aorta in ovariectomized rats compared with sham-operated controls. This increase was predominantly inhibited by treatment with 17beta-estradiol, and low-dose or high-dose 2-ME. The observed effects were unrelated to changes in serum lipids, blood glucose, or blood pressure. Our data suggested that 2-ME mediates the anti-atherosclerotic actions of estradiol at least in part by preventing monocyte adhesion to the aortic endothelium. [Abstract/Link to Full Text]

Aramata S, Han SI, Kataoka K
Roles and Regulation of Transcription Factor MafA in Islet beta-cells.
Endocr J. 2007 Aug 30;
Insulin is a critical hormone in the regulation of blood glucose levels. It is produced exclusively by pancreatic islet beta-cells. beta-cell-enriched transcription factors, such as Pdx1 and Beta2, have dual roles in the activation of the insulin gene promoter establishing beta-cell-specific insulin expression, and in the regulation of beta-cell differentiation. It was shown that MafA, a beta-cell-specific member of the Maf family of transcription factors, binds to the conserved C1/RIPE3b element of the insulin promoter. The Maf family proteins regulate tissue-specific gene expression and cell differentiation in a wide variety of tissues. MafA acts synergistically with Pdx1 and Beta2 to activate the insulin gene promoter, and mice with a targeted deletion of mafA develop age-dependent diabetes. MafA also regulates genes involved in beta-cell function such as Glucose transporter 2, Glucagons-like peptide 1 receptor, and Prohormone convertase 1/3. The abundance of MafA in beta-cells is regulated at both the transcriptional and post-translational levels by glucose and oxidative stress. This review summarizes recent progress in determining the functions and roles of MafA in the regulation of insulin gene transcription in beta-cells. [Abstract/Link to Full Text]

Tanriverdi F, Karaca Z, Oner A, Durak AC, Selcuklu A, Unluhizarci K, Kelestimur F
Complete Surgical Resolution of Bilateral Total Opthalmoplegia without Visual Field Defect in an Acromegalic Patient Presented with Pituitary Apoplexy.
Endocr J. 2007 Aug 30;
Pituitary apoplexy (PA), which is one of the most serious life-threatening complications of pituitary adenoma, is characterized by abrupt onset of headache, nausea, vomiting, visual disturbances and oculomotor paresis. Combination of oculomotor cranial nerve paralysis with normal visual fields is very rare in PA. We report a 60-year-old acromegalic man presented with panhypopituitarism and bilateral total opthalmoplegia without a visual field defect. At initial evaluation his clinical findings were compatible with adrenal crisis and eye examination revealed total opthalmoplegia, bilateral ptosis and normal vision. MRI showed a large heterogeneous mass in the pituitary fossa. Although clinical findings due to adrenal crisis improved after glucocorticoid therapy there was no improvement in opthalmoplegia and ptosis. The patient underwent transsphenoidal excision of the pituitary mass. Histological examination revealed an adenoma with large areas of hemorrhagic infarction and most of the cells were positive for GH in immunohistochemical analysis. Although opthalmoplegia was severe at presentation, total recovery was achieved 3 months after transsphenoidal surgery. Therefore the presented case clearly demonstrates that opthalmoplegia without a visual field defect due to PA has a good prognosis and early diagnosis and treatment including surgical decompression are crucially important. [Abstract/Link to Full Text]

Tabata T, Mine S, Okada Y, Tanaka Y
Low Molecular Weight Hyaluronan Increases the Uptaking of Oxidized LDL into Monocytes.
Endocr J. 2007 Aug 30;
Since accumulation and interaction of immune cells including T cells and monocytes/macrophages are involved in the processes of atherosclerosis, atherosclerosis is currently understood as an inflammatory disorder. Entrapment of extracellular matrices components such as hyaluronan by monocytes and macrophages, as well as uptake of oxidized low-density lipoprotein (ox-LDL) by these cells, plays a central role in foam cell formation and the pathogenesis of atherosclerosis. We investigated the role of CD44, the principal receptor for hyaluronic acid, and ox-LDL in scavenger receptor expression on resting monocytes prepared by counterflow centrifugal elutriation from the endothelium. Our results showed that the low-molecular weight (6.9 kDa) form of hyaluronan increased the expression of CD36 scavenger receptor; the incorporation of (125)I-labeled ox-LDL, and the transendothelial migration of monocytes, which were mediated at least in part via tyrosine kinase and the PKC pathway. Our results imply that low molecular weight hyaluronan produced in large amounts in atherosclerotic lesions induces differentiation of circulating monocytes to macrophages/foam cells and enhances the progression of atherosclerosis via the PKC pathway. Furthermore, low molecular weight hyaluronan also amplifies the migration of monocytes into inflamed atherosclerotic plaques. Thus, we propose that engagement of CD44 with low molecular weight hyaluronan is centrally involved in the inflammatory pathogenesis of athelosclerotic plaques through migration of monocytes and foamed macrophage differentiation. [Abstract/Link to Full Text]

Yasuda T, Matsuhisa M, Fujiki N, Sakamoto F, Tsuji M, Fujisawa N, Kimura M, Ishibashi R, Kaneto H, Yamasaki Y, Watarai T, Imano E
Is Central Obesity a Good Predictor of Carotid Atherosclerosis in Japanese Type 2 Diabetes with Metabolic Syndrome?
Endocr J. 2007 Aug 30;
Metabolic syndrome has been revealed to be a major risk factor for cardiovascular disease (CVD) and early mortality in non-diabetic and diabetic patients. In 2005, the International Diabetes Federation (IDF) and the Examination Committee of Criteria for Diagnosis of Metabolic Syndrome in Japan published new definitions of metabolic syndrome in which central obesity was an indispensable factor. However, the significance of this new definition to CVD in type 2 diabetes has not yet been clarified. A cross-sectional study was conducted with 294 Japanese type 2 diabetic patients without known cardiovascular disease to evaluate the association between metabolic syndrome defined by this new definition and carotid atherosclerosis, and the significance of central obesity for the prediction of the development of carotid atherosclerosis. In a multivariate regression analysis, metabolic syndrome but not central obesity was significantly associated with carotid intima-media thickness (IMT) independent of known cardiovascular risk factors (p<0.05). In addition, whereas carotid IMT was significantly increased according to the increase in the number of components of metabolic syndrome, it was not significantly different between the groups with the same number of components of metabolic syndrome with or without central obesity. These findings suggest that the prediction of the development of carotid atherosclerosis in Japanese type 2 diabetic patients could be improved by the assessment of aggregation of components of metabolic syndrome rather than with or without metabolic syndrome by this new definition. [Abstract/Link to Full Text]

Jaroenporn S, Nagaoka K, Kasahara C, Ohta R, Watanabe G, Taya K
Physiological roles of Prolactin in the Adrenocortical Response to Acute Restraint Stress.
Endocr J. 2007 Aug 30;
The present study characterized the different hormonal responses to stress in the endocrine milieu with different circulating levels of prolactin (PRL) and examined the direct effects of PRL on adrenal steroidogenic responses to adrenocorticotropic hormone (ACTH) using experimentally induced hyperprolactinemia and hypoprolactinemia male rat models. Hyperprolactinemia was induced by transplantation of two adult female rat anterior pituitary glands under the kidney capsule for 2 weeks, and hypoprolactinemia was induced by daily subcutaneous injection of 2-Bromo-alpha-Ergocryptine (CB-154) for 2 weeks. Under stress conditions, the peak levels of ACTH were significantly higher in hypoprolactinemia than normal rats. Meanwhile, the peak levels of corticosterone and progesterone were significantly higher in hyperprolactinemia than in normal and hypoprolactinemia stressed rats. Results of in vitro experiments showed that adrenocortical cells in hyperprolactinemia exhibited higher basal levels of corticosterone and progesterone rats than normal and hypoprolactinemia rats. The stimulatory effect of ACTH on corticosterone and progesterone release was higher in hyperprolactinemia than hypoprolactinemia rats. In addition, PRL increased the stimulatory effect of ACTH-induced corticosterone secretion in all rat models. These results suggest that hypoprolactinemia and hyperprolactinemia rats exhibit marked differences in the response of their hypothalamic-pituitary-adrenal (HPA) axis during acute restrain stress. Additionally, these studies emphasize that the adrenal cortex might be more sensitive to ACTH stimulation in endocrine milieu with high levels of PRL resulting in high corticosterone and progesterone release. [Abstract/Link to Full Text]

Ito K, Utsunomiya H, Yaegashi N, Sasano H
Biological Roles of Estrogen and Progesterone in Human Endometrial Carcinoma - New Developments in Potential Endocrine Therapy for Endometrial Cancer -
Endocr J. 2007 Sep 4;
Endometrial carcinoma is one of the most common female pelvic malignancies. It is well known that uterine endometrial cell proliferation is under the control of both estrogen and progesterone. In this review, results of the recent studies on the biosynthesis and action of estrogen and progestin in normal endometrium and its disorders will be summarized and the new aspects of hormonal therapies in the patients with endometrial carcinoma will be discussed including its future prospectives. We reported that the enzymes responsible for intratumoral estrogen metabolism and biosynthesis are markedly different between human breast and endometrial carcinoma, although both of them are considered "estrogen-dependent malignancies". In addition, the biological significance of Progesterone receptor (PR) isoforms is considered to differ between endometrial and breast carcinomas. Clinical data concerning Hormone replacement therapy (HRT) and estrogen-dependent cancer risk also support these findings. These basic and clinical findings help to understand the biology and provide the new knowledge for prevention, diagnosis and treatment of human endomerial carcinoma. Specific endocrine treatment of endometrial carcinoma should be explored in future, although aromatase inhibitors are the most effective endocrine treatments of estrogen-responsive breast carcinoma. Retinoid, metabolities of vitamin A, and synthetic peroxisome proliferator-activated receptor (PPAR) gamma ligands, which have been used for the treatment of insulin resistance in type II diabetes mellitus, may be the important candidates as drugs not only for prevention but also for possible endocrine treatment of endometrial carcinoma. [Abstract/Link to Full Text]

Sasaki M, Yuzawa M, Saito T, Ikoma A, Tamemoto H, Kawakami M, Ishikawa SE
New HLA DRB1 and DQB1 Haplotypes in a Pedigree of Familial Graves' Disease in Japan.
Endocr J. 2007 Sep 4;
The present study demonstrated genetic analysis of human leukocyte antigen (HLA) in a familial Graves' disease linked to autoimmune mechanism. The proband was a 17 year-old female. At 15 years, Graves' disease was diagnosed with serum TSH was <0.015 IU/ml; free T(3), 13.6 pg/ml; free T(4), 4.51 ng/dl; and TSH receptor antibody (TRAb), 94.1%. She had two brothers (19 and 13 years-old), who manifested Graves' disease at 18 and 13 years, respectively. They also had elevated TRAb as high as 48.4 and 49.1%, respectively. There was a strong family history of Graves' disease in their maternal pedigree. Namely, their two aunts and a cousin had Graves' disease, and their onset ages of Graves' disease were also during their teen-age years. However, there was no patient with Graves' disease in the paternal pedigree. We checked HLA-DRB and -DQB haplotype in the members of maternal pedigree and proband's father. The members of maternal pedigree including both affected and unaffected Graves' disease had haplotypes of DRB1*150101 and DQB1*0602, except for the cousin who had DRB1*140301 and DQB1*030101. The haplotypes of DRB1*150101 and DQB1*0602 were different from susceptible HLA types in Japanese childhood onset Graves' disease. However, two cases of Graves' disease also had HLA types of DRB1*40501 and DQB1*0401, in addition to the haplotypes of DRB1*150101 and DQB1*0602. There was no other autoimmune disease including type 1 diabetes mellitus in their family. The present findings indicated that familial Graves' disease was found mainly in the maternal females and become overt during their teen-age years. They had new HLA haplotypes distinct from those susceptibly in Japanese Graves' patients. Further study will be necessary to analyze the mutant locus of DNA to elucidate pathogenesis of familial Graves' disease. [Abstract/Link to Full Text]

Arakawa M, Hirose T, Mita T, Shimizu T, Fujitani Y, Watada H, Kawamori R
Glucose Homeostasis in a Diabetic Patient during Liver Transplantation: A Case Report.
Endocr J. 2007 Sep 4;
A 66-year-old woman with type C hepatitis had been treated for hepatocellular carcinoma (HCC) with transcatheter arterial embolization and radiofrequency ablation. Liver function worsened gradually to decompensated liver cirrhosis. She had recurrence of HCC and was later admitted to Juntendo University Hospital for living-donor liver transplantation. Although blood glucose was high, she had never been diagnosed with diabetes mellitus. No diabetes-related complications were detected at that time. We started treatment with multiple insulin injections. There is a unique time called the anhepatic phase during liver transplantation during which the liver does not exist in the body. Recent reports show that it is not necessary to administer glucose for patients with normal glucose tolerance during the anhepatic phase since plasma glucose could be maintained at normoglycemia to hyperglycemia (100-150 mg/dl). In our patient, plasma glucose concentration was rather high during the anhepatic phase without glucose administration. We analyzed the levels of blood glucose, insulin and various other hormones during the anhepatic phase. This could be the first report on glucose homeostasis during the anhepatic phase in a diabetic patient. [Abstract/Link to Full Text]

Kubo T, Furujo M, Mori S, Imai K, Ueda Y, Tsukahara K, Morita H, Ogura K, Fukuhara S, Shimizu J, Koyama T, Kanadani T, Shiraga H, Shinozuka M, Terasaki T, Hattori N
An Infant Case of Macroprolactinemia with Transient Idiopathic Central Precocious Puberty.
Endocr J. 2007 Sep 4;
Macroprolactinemia was recognized more than a decade ago as a cause of hyperprolactinemia and the prevalence of macroprolactinemia is thought to be 10%-26% of patients with hyperprolactinemia. However, there are few published reports about macroprolactinemia in childhood. We report a 7-year-and-1-month-old girl with hyperprolactinemia due to macro -prolactinemia with the complication of transient idiopathic central precocious puberty (ICPP). At the age of 6 years and 9 months, she was diagnosed with ICPP at another clinic, on the basis of isolated mammary development and increased height velocity with slightly advanced bone age. At that time, the unexpected finding of high PRL level was also observed. Four months later, she was referred to our clinic for persistently high PRL level. At this time, other endocrinological data showed prepubertal stage and we demonstrated macroprolactinemia and the presence of anti-PRL autoantibody. After other causes of hyperprolactinemia such as prolactinoma and stress were ruled out, we finally diagnosed her with hyperprolactinemia due to macroprolactinemia. Because most patients with macroprolactinemia are symptom-free despite hyperprolactinemia and drug therapy would not be indicated, macroprolactinemia should be suspected even in children to avoid unnecessary examinations and treatments. [Abstract/Link to Full Text]

Nakamura Y, Suzuki T, Sasano H
Transcription Factor GATA-6 in the Human Adrenocortex: Association with Adrenal Development and Aging.
Endocr J. 2007 Sep 4;
Transcription factor GATA-6 has been demonstrated to be expressed in the human fetal and adult adrenal cortex and has been postulated to play an important role in adrenal steroid biosynthesis. However, the status for GATA-6 expression has not been examined in detail especially in relation to adrenal development and aging. Therefore, in this study, we analyzed GATA-6 expression in 11 human fetal adrenals and 19 adrenal glands after birth using immunohistochemistry. In the fetal adrenals, the status of GATA-6 immunoreactivity in the definitive zone was significantly and directly correlated with ages of development (P<0.05) but in the fetal zone was significantly and inversely correlated with ages of development (P<0.05). After birth, GATA-6 was more abundant in the zona fasciculata compared to other zones (P<0.05) but was not related to aging of the subject. These results suggest that GATA-6 expression is involved in the regulation of corticosteroid production in both the human fetal and adult adrenals, and the changes of intra-adrenal GATA-6 expression in the human fetal adrenal plays important roles in developmental changes of both the definitive and fetal zones. [Abstract/Link to Full Text]

Akinci B, Comlekci A, Yener S, Demir T, Ozcan MA, Bayraktar F, Yesil S
Thrombin activatable fibrinolysis inhibitor antigen levels are inversely correlated with plasminogen activator inhibitor-1 antigen levels in hyperthyroid patients.
Endocr J. 2007 Sep;54(4):593-9.
Both increased and decreased fibrinolytic activity have been reported in patients with hyperthyroidism. Elevated levels of plasma plasminogen activator inhibitor-1 (PAI-1) antigen have been found in hyperthyroid patients. Thrombin activatable fibrinolysis inhibitor (TAFI) is a novel plasma protein, which inhibits fibrinolysis through removal of C-terminal lysines from partially degraded fibrin. Previously, we showed that plasma TAFI antigen levels were increased in patients with overt and subclinical hypothyroidism. The aim of this study is to investigate plasma levels of TAFI and PAI-1 antigens in hyperthyroid patients. PAI-1 and TAFI antigen levels were measured in the plasma of 29 patients with hyperthyroidism (14 overt hyperthyroid and 15 subclinical hyperthyroid), and 26 healthy individuals. Although there were increased levels of PAI-1 antigen in hyperthyroid patients, plasma TAFI antigen levels were significantly lower compared to controls (80.79 ng/ml vs. 32.42 ng/ml, p = 0.000 for PAI-1; 10.42 mug/ml vs. 12.24 mug/ml, p = 0.009 for TAFI). Elevated PAI-1 antigen levels were positively correlated with free thyroid hormones, although TAFI antigen levels were in negative correlation with free thyroxine. Furthermore, an inverse correlation between PAI-1 and TAFI antigen levels was found. Our study demonstrated that TAFI antigen levels were decreased in patients with hyperthyroidism. Inverse correlation with PAI-1 suggests that the decrease in TAFI antigen levels may be due to activation of TAFI pathway. Further studies evaluating the underlying mechanisms of low TAFI antigen levels in hyperthyroidism should be undertaken. [Abstract/Link to Full Text]

Cappelli C, Gandossi E, Castellano M, Pizzocaro C, Agosti B, Delbarba A, Pirola I, De Martino E, Agabiti Rosei E
Prognostic Value of Thyrotropin Receptor Antibodies (TRAb) in Graves' Disease: A 120 Months Prospective Study.
Endocr J. 2007 Aug 3;
In most trials, at least 30-60% of patients with Graves' disease treated with antithyroid drugs relapse within 2 years after therapy withdrawal. At present, there are no prognostic parameters available early in treatment to indicate patients likely to achieve long-term remission. Because thyrotropin receptor autoantibodies (TRAb) are specific for Graves' disease, we evaluated the ability of their levels and of their rate of change to predict long-term prognosis. In our study 216 consecutive patients with newly diagnosed Graves' disease started a therapy with methimazole. Patients were treated until they achieved euthyroidism and TRAb were measured at 6-month intervals throughout a follow up of 120 months. Our study demonstrated that at the onset of hyperthyroidism patients' age, sex, fT4 levels and goiter size had no prognostic value in predicting long-term prognosis (respectively p=0.79; p=0.98; p=0.83; p=0.89). On the contrary, at the time of diagnosis TRAb titer was a good predictor of the final outcome (p<0.001); a titer equal to (or) more than 46.5 UI/L could identify patients who had never achieved long-term remission with a sensitivity of 52% and a specificity of 78%. Also fall rate of TRAb at 6 months of follow up and after therapy withdrawal were useful to predict the final outcome (p<0.001). At 6 months of follow up the time of therapy withdrawal, a decrease of TRAb lower than 52.3% or even its increase could identify patients who had never achieved permanent remission with a sensitivity of 55% and a specificity of 79.1%. No single parameter among TRAb, satisfactory identified a sub-set of patients who achieved long remission. Accordingly to our data, the best result in predicting long term remission is probably given by the presence of at least one of the two features evaluated at 6 months (TRAb titer and/or percentage of TRAb fall rate), with a sensitivity of 63% and specificity of 88%. TRAb titers evaluated both at the onset of hyperthyroidism that at 6 months of therapy or their rate of fall at 6 months and at ATD withdrawal are predictors of outcome. However, the presence of at least one, between titers of TRAb or their rate of fall at six months, resulted to be the best predictor of remission with the higher sensitivity and specificity. [Abstract/Link to Full Text]

Izumi T
Physiological Roles of Rab27 Effectors in Regulated Exocytosis.
Endocr J. 2007 Jul 31;
Recent discoveries that Rab27a/b and their multiple effectors are involved in the regulated exocytosis of lysosome-related organelles and secretory granules have generated numerous related studies. However, not all of these studies have yielded physiologically relevant data because they were not all performed under physiological conditions. For example, "in vivo interactions" have been claimed without examination of the endogenous complex. In some studies, the only proof of interaction was between exogenously expressed proteins in cultured cells where these proteins are not normally expressed. Because regulated exocytic pathways contain highly differentiated secretory organelles, it is important to analyze the molecular interaction in cells harboring these organelles and the associated molecules. Furthermore, previous overexpression experiments to examine the effect on secretion often failed to compare the level of the exogenous protein with that of the endogenous one. Similarly, some knockdown experiments using small-interfering RNAs have only shown downregulation of the exogenously expressed protein, and not of the endogenous one. Many of the conflicting findings in previous studies may be attributable to these shortcomings. The present study summarizes our knowledge about the roles of Rab27 effectors in regulated exocytic pathways based on physiologically relevant data. [Abstract/Link to Full Text]

Sakihara S, Kageyama K, Nigawara T, Kidani Y, Suda T
Ampulla (Takotsubo) Cardiomyopathy Caused by Secondary Adrenal Insufficiency in ACTH Isolated Deficiency.
Endocr J. 2007 Sep;54(4):631-6.
We describe here a case of reversible ampulla (takotsubo) cardiomyopathy caused by secondary adrenal insufficiency in ACTH isolated deficiency. A 53-year-old woman was referred to our department for evaluation and treatment of unconsciousness. On admission, her plasma glucose level was 34 mg/dL, suggesting loss of consciousness due to hypoglycemia. Basal levels of ACTH, cortisol, and dehydroepiandrosterone sulfate in blood, and urinary free cortisol levels were all decreased. ACTH and cortisol levels were not adequately increased in response to CRH administration and the insulin tolerance test. Electrocardiography showed ST segment elevation and T wave inversion in leads V(1-6). The coronary arteries were free of organic stenosis, and a left ventriculogram revealed severe hypokinesis, particularly in the anterior and posterior walls. Based on a diagnosis of adrenocortical insufficiency caused by ACTH isolated deficiency, hydrocortisone was administered. Two weeks after treatment, ultrasound studies of the heart showed recovery of left ventricular wall motion. Activation of the sympathetic nervous system, adrenocortical failure, and hypoglycemic attack were considered to be triggering factors for the takotsubo cardiomyopathy. Careful monitoring of cardiac function and appropriate treatments for both cardiomyopathy and adrenocortical failure are required to recover cardiac dysfunction. [Abstract/Link to Full Text]

Recent Articles in Minerva Endocrinologica

No recent articles are currently available.

Recent Articles in Reproductive Biology and Endocrinology

Ivell R
Lifestyle impact and the biology of the human scrotum.
Reprod Biol Endocrinol. 2007;515.
The possession of a scrotum to contain the male gonads is a characteristic feature of almost all mammals, and appears to have evolved to allow the testes and epididymis to be exposed to a temperature a few degrees below that of core body temperature. Analysis of cryptorchid patients, and those with varicocele suggest that mild scrotal warming can be detrimental to sperm production, partly by effects on the stem cell population, and partly by effects on later stages of spermatogenesis and sperm maturation. Recent studies on the effects of clothing and lifestyle emphasize that these can also lead to chronically elevated scrotal temperatures. In particular, the wearing of nappies by infants is a cause for concern in this regard. Together all of the evidence indirectly supports the view that lifestyle factors in addition to other genetic and environmental influences could be contributing to the secular trend in declining male reproductive parameters. The challenge will be to provide relevant and targeted experimental results to support or refute the currently circumstantial evidence. [Abstract/Link to Full Text]

Fleming JS, McQuillan HJ, Millier MJ, Beaugi� CR, Livingstone V
E-cadherin expression and bromodeoxyuridine incorporation during development of ovarian inclusion cysts in age-matched breeder and incessantly ovulated CD-1 mice.
Reprod Biol Endocrinol. 2007;514.
BACKGROUND: Female CD-1/Swiss Webster mice subjected to incessant ovulation for 8 months and 12-month breeder mice both developed ovarian inclusion cysts similar to serous cystadenomas. The majority of cysts appeared to be dilated rete ovarii tubules, but high ovulation number resulted in more cortical inclusion cysts. We hypothesized that comparison of inclusion cyst pathology in animals of the same age, but with differences in total lifetime ovulation number, might allow us to determine distinguishing characteristics of the two types of cyst. METHODS: Ovaries from breeder mice (BR) or females subjected to incessant ovulation (IO) were compared at 6-, 9- and 12-months of age. Ovaries were serially sectioned and cysts characterized with regard to location and histology, E-cadherin immunoreactivity and rates of BrdU incorporation. RESULTS: Inclusion cysts developed with age in BR and IO ovaries. The majority of cysts were connected to the ovarian hilus. Two cortical inclusion cysts were observed in ten IO ovaries and one in ten BR ovaries. Low or no E-cadherin immuno-staining was seen in the OSE of all mice studied. Conversely, strong membrane immuno-staining was observed in rete ovarii epithelial cells. Variable E-cadherin immunoreactivity was seen in cells of hilar inclusion cysts, with strong staining observed in cuboidal ciliated cells and little or no staining in flat epithelial cells. Two of the three cortical cysts contained papillae, which showed E-cadherin immuno-staining at the edge of cells. However hilar and cortical cysts were not distinguishable by morphology, cell type or E-cadherin immunoreactivity. BrdU incorporation in cyst cells (1.4% [95% CI: 1.0 to 2.1]) was greater than in OSE (0.7% [95% CI: 0.4 to 1.2]) and very few BrdU-labeled cells were observed in rete ovarii at any age. Incessant ovulation significantly increased BrdU incorporation in OSE of older animals. CONCLUSION: These experiments confirm ovarian inclusion cysts develop with age in the CD-1 mouse strain, irrespective of total ovulation burden. We conclude longer periods of incessant ovulation do not lead to significant changes in inclusion cyst formation or steroidogenesis in CD-1 mice and inclusion cyst type can not be distinguished by morphology, cell proliferation rate or E-cadherin immunoreactivity. [Abstract/Link to Full Text]

Rempel LA, Austin KJ, Ritchie KJ, Yan M, Shen M, Zhang DE, Henkes LE, Hansen TR
Ubp43 gene expression is required for normal Isg15 expression and fetal development.
Reprod Biol Endocrinol. 2007;513.
BACKGROUND: Isg15 covalently modifies murine endometrial proteins in response to early pregnancy. Isg15 can also be severed from targeted proteins by a specific protease called Ubp43 (Usp18). Mice lacking Ubp43 (null) form increased conjugated Isg15 in response to interferon. The Isg15 system has not been examined in chorioallantoic placenta (CP) or mesometrial (MM) components of implantation sites beyond 9.5 days post coitum (dpc). It was hypothesized that deletion of Ubp43 would cause disregulation of Isg15 in implantation sites, and that this would affect pregnancy rates. METHODS: Heterozygous (het) Ubp43 mice were mated and MM and CP implantation sites were collected on 12.5 and 17.5 days post-coitum (dpc). RESULTS: Free and conjugated Isg15 were greater on 12.5 versus 17.5 dpc in MM. Free and conjugated Isg15 were also present in CP, but did not differ due to genotype on 12.5 dpc. However, null CP had greater free and conjugated Isg15 when compared to het/wt on 17.5 dpc. Null progeny died in utero with fetal genotype ratios (wt:het:null) of 2:5:1 on 12.5 and 2:2:1 on 17.5 dpc. Implantation sites were disrupted within the junctional zone and spongiotrophoblast, contained less vasculature based on lectin B4 staining and contained greater Isg15 mRNA and VEGF protein in Ubp43 null when compared to wt placenta. CONCLUSION: It is concluded that Isg15 and its conjugates are present in implantation sites during mid to late gestation and that deletion of Ubp43 causes an increase in free and conjugated Isg15 at the feto-maternal interface. Also, under mixed genetic background, deletion of Ubp43 results in fetal death. [Abstract/Link to Full Text]

Regev A, Goldman S, Shalev E
Semaphorin-4D (Sema-4D), the Plexin-B1 ligand, is involved in mouse ovary follicular development.
Reprod Biol Endocrinol. 2007;512.
BACKGROUND: Human Plexin-B1 is expressed in two truncated forms. The long form encodes a trans-membranal protein, while the short form, which is bound to the cell surface and partially secreted, possibly serves as a decoy receptor. Plexin receptors are trans-membrane proteins. The sema domain, found in the extracellular region, is common to all plexins, semaphorins, and the scatter factor receptors and is crucial for the biological activity and plexin receptor specificity. Semaphorin-4D/Plexin-B1 binding provides attractive and repulsive cues for the navigation of axonal growth cones, and new studies suggest that this system also plays a role in the regulation of the biological functions of endothelial cells, specifically in the control of angiogenesis. In a previous study, we have demonstrated the expression and possible role of Plexin-B1 in the mouse ovary. The present study was designed to test the hypothesis that Plexin-B1 effects are mediated by Semaphorin-4D. METHODS: In vivo expression and localization of mouse ovarian Sema-4D were tested by immunohisto-chemistry. The role of Sema-4D in follicular development was examined by in vitro growth of preantral follicles in the presence or absence of Semaphorin-4D, with or without neutralizing antibodies against Plexin-B1. Follicular growth and steroid hormone secretion rates were tested. RESULTS: Semaphorin-4D is expressed in the mouse ovary in vivo mostly in the granulosa cells and and its expression is modulated by PMSG and hCG. In the presence of Semaphorin-4D, in-vitro constant growth was observed as indicated by follicular diameter during the culture period and elevated steroid hormone secretion rates compared with control. These effects were abolished after addition of neutralizing antibodies against Plexin-B1. CONCLUSION: In the ovarian follicle, the effect of Plexin-B1 is mediated by sema-4D. [Abstract/Link to Full Text]

Hernandez ME, Soto-Cid A, Aranda-Abreu GE, D�az R, Rojas F, Garcia LI, Toledo R, Manzo J
A study of the prostate, androgens and sexual activity of male rats.
Reprod Biol Endocrinol. 2007;511.
BACKGROUND: The prostate is a sexual gland that produces important substances for the potency of sperm to fertilize eggs within the female reproductive tract, and is under complex endocrine control. Taking advantage of the peculiar behavioral pattern of copulating male rats, we developed experimental paradigms to determine the influence of sexual behavior on the level of serum testosterone, prostate androgen receptors, and mRNA for androgen receptors in male rats displaying up to four consecutive ejaculations. METHODS: The effect of four consecutive ejaculations was investigated by determining levels of (i) testosterone in serum by solid phase RIA, (ii) androgen receptors at the ventral prostate with Western Blots, and (iii) androgen receptors-mRNA with RT-PCR. Data were analyzed with a one-way ANOVA followed by a post hoc application of Dunnett's test if required. RESULTS: The constant execution of sexual behavior did not produce any change in the weight of the ventral prostate. Serum testosterone increased after the second ejaculation, and remained elevated even after four ejaculations. The androgen receptor at the ventral prostate was higher after the first to third ejaculations, but returned suddenly to baseline levels after the fourth ejaculation. The level of mRNA increased after the first ejaculation, continued to increase after the second, and reached the highest peak after the third ejaculation; however, it returned suddenly to baseline levels after the fourth ejaculation. CONCLUSION: Four consecutive ejaculations by sexually experienced male rats had important effects on the physiological responses of the ventral prostate. Fast responses were induced as a result of sexual behavior that involved an increase and decrease in androgen receptors after one and four ejaculations, respectively. However, a progressive response was observed in the elevation of mRNA for androgen receptors, which also showed a fast decrease after four ejaculations. All of these changes with the prostate gland occurred in the presence of a sustained elevation of testosterone in the serum that started after two ejaculations. A consideration of these fast-induced changes suggests that the nerve supply plays a key role in prostate physiology during the sexual behavior of male rats. [Abstract/Link to Full Text]

Doheny HC, O'Reilly MJ, Sexton DJ, Morrison JJ
THG113.31, a specific PGF2alpha receptor antagonist, induces human myometrial relaxation and BKCa channel activation.
Reprod Biol Endocrinol. 2007;510.
BACKGROUND: PGF2alpha exerts a significant contractile effect on myometrium and is central to human labour. THG113.31, a specific non-competitive PGF2alpha receptor (FP) antagonist, exerts an inhibitory effect on myometrial contractility. The BKCa channel is ubiquitously encountered in human uterine tissue and plays a significant role in modulating myometrial cell membrane potential and excitability. The objective of this study was to investigate potential BKCa channel involvement in the response of human myometrium to THG113.31. METHODS: Single and whole-cell electrophysiological BKCa channel recordings from freshly dispersed myocytes, were investigated in the presence and absence of THG113.31. Functional studies investigated the effects of THG113.31 on isolated spontaneous myometrial contractions, in the presence and absence of the BKCa channel blocker, iberiotoxin. RESULTS: Single channel recordings identified the BKCa channel as a target of THG113.31. THG113.31 significantly increased the open state probability of these channels [control 0.023+/-0.006; 10 microM THG113.31 0.087+/-0.012 (P = 0.009); and 50 microM THG113.31 0.1356+/-0.018 (P = 0.001)]. In addition, THG113.31 increased whole-cell BKCa currents over a range of membrane potentials, and this effect was reversed by 100 nanoM IbTX. Isometric tension studies demonstrated that THG113.31 exerted a significant concentration-dependent relaxant effect on human myometrial tissue and pre-incubation of strips with IbTX abolished this effect on spontaneously occurring contractions. CONCLUSION: These data suggests that activation of the BKCa channel may contribute, at least partially, to the uterorelaxant effect of THG113.31. [Abstract/Link to Full Text]

Kwee J, Elting ME, Schats R, McDonnell J, Lambalk CB
Ovarian volume and antral follicle count for the prediction of low and hyper responders with in vitro fertilization.
Reprod Biol Endocrinol. 2007;59.
BACKGROUND: The current study was designed to compare antral follicle count (AFC) and basal ovarian volume (BOV), the exogenous FSH ovarian reserve test (EFORT) and the clomiphene citrate challenge test (CCCT), with respect to their ability to predict poor and hyper responders. METHODS: One hundred and ten regularly menstruating patients, aged 18-39 years, participated in this prospective study, randomized, by a computer designed 4-blocks system study into two groups. Fifty six patients underwent a CCCT, and 54 patients underwent an EFORT. All patients underwent a transvaginal sonography to measure the basal ovarian volume and count of basal antral follicle. In all patients, the test was followed by a standard IVF treatment. The result of ovarian hyperstimulation during IVF treatment, expressed by the total number of follicles, was used as gold standard. RESULTS: The best prediction of ovarian reserve (Y) was seen in a multiple regression prediction model that included, AFC, Inhibin B-increment in the EFORT and BOV simultaneously (Y = -3.161 + 0.805 x AFC (0.258-1.352) + 0.034 x Inh. B-incr. (0.007-0.601) + 0.511 BOV (0.480-0.974) (r = 0.848, p < 0.001). Univariate logistic regression showed that the best predictors for poor response were the CCCT (ROC-AUC = 0.87), the bFSH (ROC-AUC = 0.83) and the AFC (ROC-AUC = 0.83). Multiple logistic regression analysis did not produce a better model in terms of improving the prediction of poor response. For hyper response, univariate logistic regression showed that the best predictors were AFC (ROC-AUC = 0.92) and the inhibin B-increment in the EFORT (ROC-AUC = 0.92), but AFC had better test characteristics, namely a sensitivity of 82% and a specificity 89%. Multiple logistic regression analysis did not produce a better model in terms of predicting hyper response. CONCLUSION: In conclusion AFC performs well as a test for ovarian response being superior or at least similar to complex expensive and time consuming endocrine tests. It is therefore likely to be the test for general practise. [Abstract/Link to Full Text]

Beleza-Meireles A, Barbaro M, Wedell A, T�h�nen V, Nordenskj�ld A
Studies of a co-chaperone of the androgen receptor, FKBP52, as candidate for hypospadias.
Reprod Biol Endocrinol. 2007;58.
BACKGROUND: Hypospadias is a common inborn error of the male urethral development, for which the aetiology is still elusive. Polymorphic variants in genes involved in the masculinisation of male genitalia, such as the androgen receptor, have been associated with some cases of hypospadias. Co-regulators of the androgen receptor start being acknowledged as possible candidates for hormone-resistance instances, which could account for hypospadias. One such molecule, the protein FKBP52, coded by the FKBP4 gene, has an important physiological role in up-regulating androgen receptor activity, an essential step in the development of the male external genitalia. The presence of hypospadias in mice lacking fkbp52 encouraged us to study the sequence and the expression of FKBP4 in boys with isolated hypospadias. PATIENTS AND METHODS: The expression of FKBP52 in the genital skin of boys with hypospadias and in healthy controls was tested by immunohistochemistry. Mutation screening in the FKBF4 gene was performed in ninety-one boys with non syndromic hypospadias. Additionally, two polymorphisms were typed in a larger cohort. RESULTS: Immunohistochemistry shows epithelial expression of FKBP52 in the epidermis of the penile skin. No apparent difference in the FKBP52 expression was detected in healthy controls, mild or severe hypospadias patients. No sequence variants in the FKBP4 gene have implicated in hypospadias in our study. CONCLUSION: FKBP52 is likely to play a role in growth and development of the male genitalia, since it is expressed in the genital skin of prepubertal boys; however alterations in the sequence and in the expression of the FKBP4 gene are not a common cause of non-syndromic hypospadias. [Abstract/Link to Full Text]

Andersen ML, Martins RC, Alvarenga TA, Antunes IB, Papale LA, Tufik S
Progesterone reduces erectile dysfunction in sleep-deprived spontaneously hypertensive rats.
Reprod Biol Endocrinol. 2007;57.
BACKGROUND: Paradoxical sleep deprivation (PSD) associated with cocaine has been shown to enhance genital reflexes (penile erection-PE and ejaculation-EJ) in Wistar rats. Since hypertension predisposes males to erectile dysfunction, the aim of the present study was to investigate the effects of PSD on genital reflexes in the spontaneously hypertensive rat (SHR) compared to the Wistar strain. We also extended our study to examine how PSD affect steroid hormone concentrations involved in genital events in both experimental models. METHODS: The first experiment investigated the effects of PSD on genital reflexes of Wistar and SHR rats challenged by saline and cocaine (n = 10/group). To further examine the impact of the PSD on concentrations of sexual hormones, we performed a hormonal analysis of testosterone and progesterone in the Wistar and in SHR strains. Since after PSD progesterone concentrations decreased in the SHR compared to the Wistar PSD group we extended our study by investigating whether progesterone (25 mg/kg or 50 mg/kg) or testosterone (0.5 mg/kg or 1.0 mg/kg) administration during PSD would have a facilitator effect on the occurrence of genital reflexes in this hypertensive strain. RESULTS: A 4-day period of PSD induced PE in 50% of the Wistar rats against 10% for the SHR. These genital reflexes was potentiated by cocaine in Wistar rats whereas this scenario did not promote significant enhancement in PE and EJ in hypertensive rats, and the percentage of SHR displaying genital reflexes still figured significantly lower than that of the Wistar strain. As for hormone concentrations, both sleep-deprived Wistar and SHR showed lower testosterone concentrations than their respective controls. Sleep deprivation promoted an increase in concentrations of progesterone in Wistar rats, whereas no significant alterations were found after PSD in the SHR strain, which did not present enhancement in erectile responses. In order to explore the role of progesterone in the occurrence of genital reflexes, SHR were treated daily during the sleep deprivation period with progesterone; after the administration of this hormone and challenge with cocaine, we observed a significant increase in erectile events compared with the vehicle PSD SHR+cocaine group. CONCLUSION: Our data showed that the low frequency of genital reflexes found in SHR sleep deprived rats may be attributed to the lower concentrations of progesterone in these rats, based on the observation that progesterone replacement increased genital reflexes in this strain. [Abstract/Link to Full Text]

Lunghi L, Ferretti ME, Medici S, Biondi C, Vesce F
Control of human trophoblast function.
Reprod Biol Endocrinol. 2007;56.
The trophoblast, i.e. the peripheral part of the human conceptus, exerts a crucial role in implantation and placentation. Both processes properly occur as a consequence of an intimate dialogue between fetal and maternal tissues, fulfilled by membrane ligands and receptors, as well as by hormone and local factor release. During blastocyst implantation, generation of distinct trophoblast cell types begins, namely the villous and the extravillous trophoblast, the former of which is devoted to fetal-maternal exchanges and the latter binds the placental body to the uterine wall. Physiological placentation is characterized by the invasion of the uterine spiral arteries by extravillous trophoblast cells arising from anchoring villi. Due to this invasion, the arterial structure is replaced by amorphous fibrinoid material and endovascular trophoblastic cells. This transformation establishes a low-resistance, high-capacity perfusion system from the radial arteries to the intervillous space, in which the villous tree is embedded. The physiology of pregnancy depends upon the orderly progress of structural and functional changes of villous and extravillous trophoblast, whereas a derangement of such processes can lead to different types of complications of varying degrees of gravity, including possible pregnancy loss and maternal life-threatening diseases. In this review we describe the mechanisms which regulate trophoblast differentiation, proliferation, migration and invasiveness, and the alterations in these mechanisms which lead to pathological conditions. Furthermore, based on the growing evidence that proper inflammatory changes and oxidative balance are needed for successful gestation, we explain the mechanisms by which agents able to influence such processes may be useful in the prevention and treatment of pregnancy disorders. [Abstract/Link to Full Text]

Cannon MJ, Davis JS, Pate JL
Expression of costimulatory molecules in the bovine corpus luteum.
Reprod Biol Endocrinol. 2007;55.
BACKGROUND: Bovine luteal parenchymal cells express class II major histocompatibility complex (MHC) molecules and stimulate class II MHC-dependent activation of T cells in vitro. The ability of a class II MHC-expressing cell type to elicit a response from T cells in vivo is also dependent on expression of costimulatory molecules by the antigen presenting cell and delivery of a costimulatory signal to the T cell. Whether bovine luteal parenchymal cells express costimulatory molecules and can deliver the costimulatory signal is currently unknown. METHODS: Bovine luteal tissue was collected during the early (day 5; day of estrus = day 0), mid (day 11-12), or late (day 18) luteal phase of the estrous cycle, and at 0, 0.5, 1, 4, 12 or 24 hours following administration of PGF2alpha to cows on day 10 of the estrous cycle. Northern analysis was used to measure CD80 or CD86 mRNA concentrations in luteal tissue samples. Mixed luteal parenchymal cell cultures and purified luteal endothelial cell cultures were prepared, and real-time RT-PCR was used to examine the presence of CD80 and CD86 mRNA in each culture type. Monoclonal antibodies to CD80 and CD86 were added to a mixed luteal parenchymal cell-T cell co-culture in vitro T cell proliferation assay to assess the functional significance of costimulatory molecules on activation of T lymphocytes by luteal parenchymal cells. RESULTS: Northern analysis revealed CD80 and CD86 mRNAs in luteal tissue, with greatest steady-state concentrations at midcycle. CD80 and CD86 mRNAs were detected in mixed luteal parenchymal cell cultures, but only slight amounts of CD80 (and not CD86) mRNA were detected in cultures of luteal endothelial cells. Luteinizing hormone, PGF2alpha and TNF-alpha were without effect on concentrations of CD80 or CD86 mRNA in mixed luteal parenchymal cells cultures. Anti-CD80 or anti-CD86 monoclonal antibodies inhibited T cell proliferation in the in vitro T cell proliferation assay. CONCLUSION: It can be concluded from this study that parenchymal cells within the bovine CL express functional costimulatory molecules that facilitate interactions between with T cells, and these components of the antigen presentation pathway are expressed maximally in the midcycle CL. [Abstract/Link to Full Text]

Aflalo ED, Sod-Moriah UA, Potashnik G, Har-Vardi I
EGF increases expression and activity of PAs in preimplantation rat embryos and their implantation rate.
Reprod Biol Endocrinol. 2007;54.
BACKGROUND: Embryo implantation plays a major role in embryogenesis and the outcome of pregnancy. Plasminogen activators (PAs) have been implicated in mammalian fertilization, early stages of development and embryo implantation. As in-vitro developing embryos resulted in lower implantation rate than those developed in-vivo we assume that a reduced PAs activity may be involved.In the present work we studied the effect of EGF on PAs activity, quantity and embryo implantation. METHODS: Zygotes were flushed from rat oviducts on day one of pregnancy and grown in-vitro in R1ECM supplemented with EGF (10 ng/ml) and were grown up to the blastocyst stage. The control groups were grown in the same medium without EGF. The distribution and quantity of the PAs were examined using fluorescence immunohistochemistry followed by measurement of PAs activity using the chromogenic assay. Implantation rate was studied using the embryo donation model. RESULTS: PAs distribution in the embryos was the same in EGF treated and untreated embryos. Both PAs were localized in the blastocysts' trophectoderm, supporting the assumption that PAs play a role in the implantation process in rats.EGF increased the quantity of uPA at all stages studied but the 8-cell stage as compared with controls. The tissue type PA (tPA) content was unaffected except the 8-cell stage, which was increased. The activity of uPA increased gradually towards the blastocyst stage and more so due to the presence of EGF. The activity of tPA did not vary with the advancing developmental stages although it was also increased by EGF.The presence of EGF during the preimplantation development doubled the rate of implantation of the treated group as compared with controls. [Abstract/Link to Full Text]

Wang H, Stjernholm YV
Plasma membrane receptor mediated MAPK signaling pathways are activated in human uterine cervix at parturition.
Reprod Biol Endocrinol. 2007;53.
BACKGROUND: Cervical ripening resembles an inflammatory reaction. Estrogens induce leukocyte migration into tissue and factors promoting cervical remodeling and labor, although the mechanisms are only partially known. The aim of this study was to investigate whether plasma membrane receptor mediated pathways, known to be activated by estrogens and proinflammatory compounds, are involved in cervical ripening before labor. METHODS: The expression and distribution of mitogen activated protein kinases (MAPK), which transduce extracellular signals into intracellular responses through phosphorylation, and their intracellular targets transcription factors c-Jun and c-Fos proteins (AP-1) were analysed in cervical biopsies from term pregnant women (TP), immediately after parturition (PP), and from non-pregnant women (NP). Immunohistochemistry and RT-PCR techniques were used. RESULTS: Cell-specific alterations in the immunostaining pattern for MAPK were observed. The expressions of activated, phosphorylated MAPK forms pERK1/2, pJNK and p38MAPK were significantly increased in cervical stroma until TP and pERK1/2 expression was significantly enhanced in PP group. c-Jun was significantly increased in cervical stroma and smooth muscle in TP as compared to NP group. c-Fos was significantly increased in stroma, squamous epithelium and glandular epithelium in PP as compared to TP group. CONCLUSION: We report, for the first time, cell-specific activation of pMAPKs and their targets transcription factors c-Fos and c-Jun (AP-1) proteins in human uterine cervix until term pregnancy, and immediately after parturition. These results suggest a role for MAPK activation in cervical ripening before labor. [Abstract/Link to Full Text]

della Ragione T, Verheyen G, Papanikolaou EG, Van Landuyt L, Devroey P, Van Steirteghem A
Developmental stage on day-5 and fragmentation rate on day-3 can influence the implantation potential of top-quality blastocysts in IVF cycles with single embryo transfer.
Reprod Biol Endocrinol. 2007;52.
BACKGROUND: In IVF-ICSI cycles with single embryo transfer (SET), embryo selection for transfer is of crucial importance. The present study aimed to define which embryo parameters might be related to the implantation potential of advanced blastocysts. METHODS: Overall, in 203 cycles with SET, developmental characteristics of 93 implanted (group A) and 110 non-implanted (group B) advanced blastocysts of good quality were compared. The following developmental parameters were assessed in the two groups: normal fertilization, developmental stage on day 5, number of blastomeres on day 2 and on day 3, fragmentation rate on day 3, compaction on day 4 and cleavage pattern on day 2 and day 3. RESULTS: Expanded blastocysts compared to full blastocysts have higher implantation potential (56.5% vs. 29.3%, p < 0.05). In group B, a higher proportion of advanced blastocysts showed between 10% and 50% anucleated fragments on day 3 than in group A (23.6 vs 11.8, P = 0.03). Advanced blastocysts with >10-50% fragments on day 3 showed a significant lower implantation (29.7%) than those with < or = 10%fragments (49.4%, P = 0.03). All the other parameters analysed were comparable for the two groups. CONCLUSION: Developmental stage on day 5 and fragmentation rate on day 3 were related to the implantation potential of advanced blastocysts and should also be taken into account in the selection of the best advanced blastocyst for transfer. [Abstract/Link to Full Text]

Bone W, Walden CM, Fritsch M, Voigtmann U, Leifke E, Gottwald U, Boomkamp S, Platt FM, van der Spoel AC
The sensitivity of murine spermiogenesis to miglustat is a quantitative trait: a pharmacogenetic study.
Reprod Biol Endocrinol. 2007;51.
BACKGROUND: A major event in the post-meiotic development of male germ cells is the formation of the acrosome. This process can be perturbed in C57BL/6 mice by administration of the small molecule miglustat (N-butyldeoxynojirimycin, NB-DNJ). The miglustat-treated mice produce morphologically abnormal spermatozoa that lack acrosomes and are poorly motile. In C57BL/6 mice, miglustat can be used to maintain long-term reversible infertility. In contrast, when miglustat was evaluated in normal men, it did not affect spermatogenesis. To gain more insight into this species difference we have now evaluated the reproductive effects of miglustat in rabbits, in multiple mouse strains and in interstrain hybrid mice. METHODS: Male mice of 18 inbred strains were administered miglustat orally or via miniosmotic pumps. Rabbits were given the compound in their food. Fourth-generation interstrain hybrid mice, bred from C57BL/6 and FVB/N mice (which differ in their response to miglustat), also received the drug. Data on fertility (natural mating), sperm motility and morphology, acrosome status, and serum drug levels were collected. RESULTS: In rabbits the drug did not induce aberrations of sperm shape or motility, although the serum level of miglustat in rabbits far exceeded the level in C57BL/6 mice (8.4 microM and 0.5 microM, respectively). In some strains of the Swiss and Castle lineages of inbred mice miglustat did not cause infertility, severe morphological sperm aberrations or reduced sperm motility. In these strains miglustat only had milder effects. However, miglustat strongly disturbed acrosome and sperm nucleus development in AKR/J and BALB/c mice and in a number of C57BL/6-related strains. The consequences of drug administration in the interstrain hybrid mice were highly variable. Judging by the number of grossly abnormal spermatozoa, these genetically heterogeneous mice displayed a continuous range of intermediate responses, distinct from either of their parental strains. CONCLUSION: The effects of miglustat on spermatogenesis in mice are strain-dependent, while in rabbits the drug is ineffective. Evaluation of interstrain hybrid mice indicated that the sensitivity of spermatogenesis to miglustat is a quantitative trait. These studies pave the way for identifying the genetic factors underlying the strain/species differences in the effect of miglustat. [Abstract/Link to Full Text]

Pinto PI, Singh PB, Conde�a JB, Teod�sio HR, Power DM, Can�rio AV
ICI 182,780 has agonistic effects and synergizes with estradiol-17 beta in fish liver, but not in testis.
Reprod Biol Endocrinol. 2006;467.
BACKGROUND: ICI 182,780 (ICI) belongs to a new class of antiestrogens developed to be pure estrogen antagonists and, in addition to its therapeutic use, it has been used to knock-out estrogen and estrogen receptor (ER) actions in several mammalian species. In the present study, the effects and mechanism of action of ICI were investigated in the teleost fish, sea bream (Sparus auratus). METHODS: Three independent in vivo experiments were performed in which mature male tilapia (Oreochromis mossambicus) or sea bream received intra-peritoneal implants containing estradiol-17 beta (E2), ICI or a combination of both compounds. The effects of E2 and ICI on plasma calcium levels were measured and hepatic and testicular gene expression of the three ER subtypes, ER alpha, ER beta a and ER beta b, and the estrogen-responsive genes, vitellogenin II and choriogenin L, were analyzed by semi-quantitative RT-PCR in sea bream. RESULTS: E2 treatment caused an increase in calcium levels in tilapia, while ICI alone had no noticeable effect, as expected. However, pretreatment with ICI synergistically potentiated the effect of E2 on plasma calcium in both species. ICI mimicked some E2 actions in gene expression in sea bream liver upregulating ER alpha, vitellogenin II and choriogenin L, although, unlike E2, it did not downregulate ER beta a and ER beta b. In contrast, no effects of E2 or ICI alone were detected in the expression of ERs in testis, while vitellogenin II and choriogenin L were upregulated by E2 but not ICI. Finally, pretreatment with ICI had a synergistic effect on the hepatic E2 down-regulation of ER beta b, but apparently blocked the ER alpha up-regulation by E2. CONCLUSION: These results demonstrate that ICI has agonistic effects on several typical estrogenic responses in fish, but its actions are tissue-specific. The mechanisms for the ICI agonistic activity are still unknown; although the ICI induced up-regulation of ER alpha mRNA could be one of the factors contributing to the cellular response. [Abstract/Link to Full Text]

Casais M, Delgado SM, Sosa Z, Telleria CM, Rastrilla AM
The celiac ganglion modulates LH-induced inhibition of androstenedione release in late pregnant rat ovaries.
Reprod Biol Endocrinol. 2006;466.
BACKGROUND: Although the control of ovarian production of steroid hormones is mainly of endocrine nature, there is increasing evidence that the nervous system also influences ovarian steroidogenic output. The purpose of this work was to study whether the celiac ganglion modulates, via the superior ovarian nerve, the anti-steroidogenic effect of LH in the rat ovary. Using mid- and late-pregnant rats, we set up to study: 1) the influence of the noradrenergic stimulation of the celiac ganglion on the ovarian production of the luteotropic hormone androstenedione; 2) the modulatory effect of noradrenaline at the celiac ganglion on the anti-steroidogenic effect of LH in the ovary; and 3) the involvement of catecholaminergic neurotransmitters released in the ovary upon the combination of noradrenergic stimulation of the celiac ganglion and LH treatment of the ovary. METHODS: The ex vivo celiac ganglion-superior ovarian nerve-ovary integrated system was used. This model allows studying in vitro how direct neural connections from the celiac ganglion regulate ovarian steroidogenic output. The system was incubated in buffer solution with the ganglion and the ovary located in different compartments and linked by the superior ovarian nerve. Three experiments were designed with the addition of: 1) noradrenaline in the ganglion compartment; 2) LH in the ovarian compartment; and 3) noradrenaline and LH in the ganglion and ovarian compartments, respectively. Rats of 15, 19, 20 and 21 days of pregnancy were used, and, as an end point, the concentration of the luteotropic hormone androstenedione was measured in the ovarian compartment by RIA at various times of incubation. For some of the experimental paradigms the concentration of various catecholamines (dihydroxyphenylalanine, dopamine, noradrenaline and adrenaline) was also measured in the ovarian compartment by HPLC. RESULTS: The most relevant result concerning the action of noradrenaline in the celiac ganglion was found on day 21 of pregnancy resulting in the inhibition of androstenedione release from the ovarian compartment. In addition on day 15 of pregnancy, LH placed in the ovarian compartment led to an inhibition of the release of androstenedione, and this inhibitory effect was further reinforced by the joint action of noradrenaline in the celiac ganglion and LH in the ovary. The levels of catecholamines in the ovarian compartment showed differences among the experiments; of significance, the joint treatment of noradrenaline in the celiac ganglion and LH in the ovary resulted in a remarkable increase in the ovarian levels of noradrenaline and adrenaline when compared to the effect achieved by either one of the compounds added alone. CONCLUSION: Our results demonstrate that the noradrenergic stimulation of the celiac ganglion reinforces the LH-induced inhibition of androstenedione production by the ovary of late pregnant rats, and that this effect is associated with marked changes in the release of catecholamines in the ovary. [Abstract/Link to Full Text]

Hirsbrunner G, Burkhardt HW, Steiner A
Effects of a single administration of prostaglandin F2alpha, or a combination of prostaglandin F2alpha and prostaglandin E2, or placebo on fertility variables in dairy cows 3-5 weeks post partum, a randomized, double-blind clinical trial.
Reprod Biol Endocrinol. 2006;465.
BACKGROUND: Delayed uterine involution has negative effects on the fertility of cows; use of prostaglandin F2alpha alone as a single treatment has not been shown to consistently improve fertility. Combined administration of PGF2alpha and PGE2 increased uterine pressure in healthy cows. We hypothesized, that the combination of both prostaglandins would accelerate uterine involution and have, therefore, a positive effect on fertility variables. In commercial dairy farming, the benefit of a single post partum combined prostaglandin treatment should be demonstrated. METHODS: 383 cows from commercial dairy farms were included in this study. Uterine size and secretion were evaluated at treatment 21-35 days post partum and 14 days later. Cows were randomly allocated to one of three treatment groups: PGF2alpha and PGE2, PGF2alpha or placebo. For every animal participating in the study, the following reproduction variables were recorded: Interval from calving to first insemination, days open, number of artificial inseminations (AI) to conception; subsequent treatment of uterus, subsequent treatment of ovaries. Plasma progesterone level at time of treatment was used as a covariable. For continuous measurements, analysis of variance was performed. Fisher's exact test for categorical non-ordered data and exact Kruskal-Wallis test for ordered data were used; pairwise group comparisons with Bonferroni adjustment of significance level were performed. RESULTS: There was no significant difference among treatment groups in uterine size. Furthermore, there was no significant difference among treatments concerning days open, number of AI, and subsequent treatment of uterus and ovaries. Days from calving to first insemination tended to be shorter for cows with low progesterone level given PGF2alpha and PGE2 in combination than for the placebo-group (P = 0.024). CONCLUSION: The results of this study indicate that the administration of PGF2alpha or a combination of PGF2alpha and PGE2 21 to 35 days post partum had no beneficial effect upon measured fertility variables. The exception was a tendency for a shorter interval from calving to first insemination after administration of the combination of PGF2alpha and PGE2, as compared to the placebo group. Further research should be done in herds with reduced fertility and/or an increased incidence of postpartum vaginal discharge. [Abstract/Link to Full Text]

Walther N, Jansen M, Akbary W, Ivell R
Differentiation-specific action of orphan nuclear receptor NR5A1 (SF-1): transcriptional regulation in luteinizing bovine theca cells.
Reprod Biol Endocrinol. 2006;464.
BACKGROUND: The orphan nuclear receptor NR5A1 (steroidogenic factor-1, SF-1) is a master regulator of tissue-specific gene expression in reproductive and steroidogenic tissues. Two activating functions, AF-1 and AF-2, have been described to function in a cooperative manner to recruit transcriptional coactivators to the promoter regions of NR5A1-controlled genes. METHODS: The role of the NR5A1 activating functions AF-1 and AF-2 was studied in primary bovine theca cells. Bovine theca cells were infected with recombinant adenovirus vectors over-expressing wild-type NR5A1 or NR5A1 mutants, in which one of the activating functions of this orphan nuclear receptor had been impaired. Under different culture conditions, theca cell-specific transcript levels were measured by reverse transcription and real-time PCR. RESULTS: Under culture conditions optimized for cell growth, transcriptional up-regulation of CYP11A1 (P450 side chain-cleavage enzyme) and INSL3 (Insulin-like factor 3, Relaxin-like factor (RLF)) was found to be dependent on the presence of NR5A1 carrying an intact AF-2. Under conditions inducing luteal differentiation of theca cells, CYP11A1 and STAR (Steroidogenic acute regulatory protein) were up-regulated by the action of luteinizing hormone (LH), whereas the differentiation-specific up-regulation of INSL3 was suppressed by LH in luteinizing theca cells. Inhibition of insulin- or IGF1- (insulin-like growth factor I) dependent signal transduction by the RAF1 kinase inhibitor GW5074 and the mitogen-activated protein kinase kinase inhibitor PD98059 resulted in the finding that RAF1 kinase inhibition was able to counteract the LH-dependent regulation of NR5A1-controlled genes, whereas inhibition of the mitogen-activated protein kinase (MAP kinase) pathway did not have any significant effect. CONCLUSION: The regulation of the three NR5A1-controlled genes CYPA11, STAR, and INSL3 in luteinizing theca cells apparently is not dependent on NR5A1 activating functions AF-1 or AF-2. Activation of AF-1 here even appears to have an impairing effect on NR5A1 transcriptional activity, implying that up-regulation of NR5A1-controlled genes uses a different pathway. Our results might be explained by the possible existence of an interconnection between the RAF1 kinase and the cyclic AMP-protein kinase A pathway. Such a non-classical regulatory pathway might play an important role in the control of gene expression in reproductive and steroidogenic tissues. [Abstract/Link to Full Text]

El-Darwish KS, Parvinen M, Toppari J
Differential expression of members of the E2F family of transcription factors in rodent testes.
Reprod Biol Endocrinol. 2006;463.
BACKGROUND: The E2F family of transcription factors is required for the activation or repression of differentially expressed gene programs during the cell cycle in normal and abnormal development of tissues. We previously determined that members of the retinoblastoma protein family that interacts with the E2F family are differentially expressed and localized in almost all the different cell types and tissues of the testis and in response to known endocrine disruptors. In this study, the cell-specific and stage-specific expression of members of the E2F proteins has been elucidated. METHODS: We used immunohistochemical (IHC) analysis of tissue sections and Western blot analysis of proteins, from whole testis and microdissected stages of seminiferous tubules to study the differential expression of the E2F proteins. RESULTS: For most of the five E2F family members studied, the localizations appear conserved in the two most commonly studied rodent models, mice and rats, with some notable differences. Comparisons between wild type and E2F-1 knockout mice revealed that the level of E2F-1 protein is stage-specific and most abundant in leptotene to early pachytene spermatocytes of stages IX to XI of mouse while strong staining of E2F-1 in some cells close to the basal lamina of rat tubules suggest that it may also be expressed in undifferentiated spermatogonia. The age-dependent development of a Sertoli-cell-only phenotype in seminiferous tubules of E2F-1 knockout males corroborates this, and indicates that E2F-1 is required for spermatogonial stem cell renewal. Interestingly, E2F-3 appears in both terminally differentiated Sertoli cells, as well as spermatogonial cells in the differentiative pathway, while the remaining member of the activating E2Fs, E2F-2 is most concentrated in spermatocytes of mid to late prophase of meiosis. Comparisons between wildtype and E2F-4 knockout mice demonstrated that the level of E2F-4 protein displays a distinct profile of stage-specificity compared to E2F-1, which is probably related to its prevalence and role in Sertoli cells. IHC of rat testis indicates that localization of E2F-5 is distinct from that of E2F-4 and overlaps those of E2F-1 and E2F-2. CONCLUSION: The E2F-1 represents the subfamily of transcription factors required during stages of DNA replication and gene expression for development of germ cells and the E2F-4 represents the subfamily of transcription factors that help maintain gene expression for a terminally differentiated state within the testis. [Abstract/Link to Full Text]

Minervini F, Giannoccaro A, Fornelli F, Dell'Aquila ME, Minoia P, Visconti A
Influence of mycotoxin zearalenone and its derivatives (alpha and beta zearalenol) on apoptosis and proliferation of cultured granulosa cells from equine ovaries.
Reprod Biol Endocrinol. 2006;462.
BACKGROUND: The mycotoxin zearalenone (ZEA) and its derivatives, alpha and beta-zearalenol (alpha and beta-ZOL), synthesized by genera Fusarium, often occur as contaminants in cereal grains and animal feeds. The importance of ZEA on reproductive disorders is well known in domestic animals species, particularly in swine and cattle. In the horse, limited data are available to date on the influence of dietary exposure to ZEA on reproductive health and on its in vitro effects on reproductive cells. The aim of this study was to evaluate the effects of ZEA and its derivatives, alpha and beta-ZOL, on granulosa cells (GCs) from the ovaries of cycling mares. METHODS: The cell proliferation was evaluated by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test after 3 days exposure at different concentrations of ZEA and its derivatives (from 1 x 10-7 to 0.1 microM). The apoptosis induction was evaluated after 1 day exposure, by DNA analysis using flow cytometry. RESULTS: An increase in cell proliferation with respect to the control was observed in the presence of ZEA at 1 x 10-3 and 1 x 10-4 microM and apoptosis was induced by all mycotoxins at different concentrations. CONCLUSION: The simultaneous presence of apoptosis and proliferation in GC cultures treated with zearalenones could indicate that these mycotoxins could be effective in inducing follicular atresia. These effects of zearalenones may result from both direct interaction with oestrogen-receptors as well as interaction with the enzymes 3alpha (beta)-hydroxysteroid dehydrogenase (HSD), involved in the synthesis and metabolism of endogenous steroid hormones. These cellular disturbances, described for the first time in equine GCs cultured in vitro, could be hypothesized as referred to reproductive failures of unknown ethiology in the mare. [Abstract/Link to Full Text]

Chandrakanthan V, Li A, Chami O, O'Neill C
Effects of in vitro fertilization and embryo culture on TRP53 and Bax expression in B6 mouse embryos.
Reprod Biol Endocrinol. 2006;461.
In the mouse, embryo culture results in a characteristic phenotype of retarded embryo preimplantation development and reduced numbers of cells within embryos. The expression of TRP53 is central to the regulation of the cell's capacity to proliferate and survive. In this study we found that Trp53 mRNA is expressed throughout the preimplantation stage of development. Levels of TRP53 protein expression were low during the cleavage stages and increased at the morula and blastocyst stages in B6 embryos collected from the reproductive tract. Embryos collected at the zygote stage and cultured for 96 h also showed low levels of TRP53 expression at precompaction stages. There were higher levels of TRP53 in cultured morula and the level in cultured blastocysts was clearly increased above blastocysts collected directly from the uterus. Immunolocalization of TRP53 showed that its increased expression in cultured blastocysts corresponded with a marked accumulation of TRP53 within the nuclei of embryonic cells. This pattern of expression was enhanced in embryos produced by in vitro fertilization and subjected to culture. The TRP53 was transcriptionally active since culture also induced increased expression of Bax, yet this did not occur in embryos lacking Trp53 (Trp53-/-). The rate of development of Trp53-/- zygotes to the blastocyst stage was not different to wildtype controls when embryos were cultured in groups of ten but was significantly faster when cultured individually. The results show that zygote culture resulted in the accumulation of transcription activity of TRP53 in the resulting blastocysts. This accounts for the adverse effects of culture of embryos individually, but does not appear to be the sole cause of the retarded preimplantation stage growth phenotype associated with culture in vitro. [Abstract/Link to Full Text]

Sharpe RL, Drolet M, MacLatchy DL
Investigation of de novo cholesterol synthetic capacity in the gonads of goldfish (Carassius auratus) exposed to the phytosterol beta-sitosterol.
Reprod Biol Endocrinol. 2006;460.
Total and intra-mitochondrial gonadal cholesterol concentrations are decreased in fish exposed to the phytoestrogen beta-sitosterol (beta-sit). The present study examined the potential for beta-sit to disrupt de novo cholesterol synthesis in the gonads of goldfish exposed to 200 microgram/g beta-sit and 10 microgram/g 17beta-estradiol (E2; estrogenic control) by intra-peritoneal Silastic implants for 21 days. The de novo cholesterol synthetic capacity was estimated by incubating gonadal tissue with 14C-acetate for a period of 18 hours, followed by chloroform/methanol lipid extraction and thin layer chromatography (TLC) lipid separation. Lipid classes were confirmed using infrared spectroscopy. Plasma testosterone (T) and total cholesterol concentration were measured and gonadosomatic index (GSI) was calculated. Plasma T was significantly reduced in male beta-sit-treated fish compared to control and E2-treated fish (p < 0.001). 14C-Acetate incorporation into cholesterol and cholesterol esters was not significantly different among treatment groups for male and female fish, however, 14C-enrichment was higher than expected in both triglycerides (TG) and free fatty acids (FFA). FFA incorporation was significantly higher in male control fish than either beta-sit or E2 treatments (p = 0.005). Plasma cholesterol concentration was significantly increased in the male beta-sit treatment group compared to controls (p = 0.027). These results indicate gonadal de novo cholesterol biosynthetic capacity is not disrupted by beta-sit or E2 treatment in early recrudescing male or female goldfish, while plasma cholesterol and steroid concentrations are sensitive to beta-sit exposure. [Abstract/Link to Full Text]

Lessey BA, Palomino WA, Apparao K, Young SL, Lininger RA
Estrogen receptor-alpha (ER-alpha) and defects in uterine receptivity in women.
Reprod Biol Endocrinol. 2006 Oct 9;4 Suppl 1S9.
ABSTRACT : Endometriosis is a disorder that affects 5% of the normal population but is present in up to 40% of women with pelvic pain and/or infertility. Recent evidence suggests that the endometrium of women with endometriosis exhibits progesterone insensitivity. One endometrial protein that fluctuates in response to progesterone is the estrogen receptor-alpha (ER alpha), being down-regulated at the time of peak progesterone secretion during the window of implantation. Here we demonstrate that the biomarker of uterine receptivity, beta 3 integrin subunit, is reduced or absent in some women with endometriosis and that such defects are accompanied by inappropriate over-expression of ER alpha during the mid-secretory phase. Using a well-differentiated endometrial cell line we showed that the beta 3 integrin protein is negatively regulated by estrogen and positively regulated by epidermal growth factor (EGF). By competing against estrogen with various selective estrogen receptor modulators (SERMs) and estrogen receptor agonists and antagonists, inhibition of expression of the beta 3 integrin by estrogen can be mitigated. In conclusion, we hypothesize that certain types of uterine receptivity defects may be caused by the loss of appropriate ER alpha down-regulation in the mid-secretory phase, leading to defects in uterine receptivity. Such changes might be effectively treated by timely administration of the appropriate anti-estrogens to artificially block ER alpha and restore normal patterns of gene expression. Such treatments will require further clinical studies. [Abstract/Link to Full Text]

Chwalisz K, Garg R, Brenner R, Slayden O, Winkel C, Elger W
Role of nonhuman primate models in the discovery and clinical development of selective progesterone receptor modulators (SPRMs).
Reprod Biol Endocrinol. 2006 Oct 9;4 Suppl 1S8.
ABSTRACT : Selective progesterone receptor modulators (SPRMs) represent a new class of progesterone receptor ligands that exert clinically relevant tissue-selective progesterone agonist, antagonist, partial, or mixed agonist/antagonist effects on various progesterone target tissues in an in vivo situation depending on the biological action studied. The SPRM asoprisnil is being studied in women with symptomatic uterine leiomyomata and endometriosis. Asoprisnil shows a high degree of uterine selectivity as compared to effects on ovulation or ovarian hormone secretion in humans. It induces amenorrhea and decreases leiomyoma volume in a dose-dependent manner in the presence of follicular phase estrogen concentrations. It also has endometrial antiproliferative effects. In pregnant animals, the myometrial, i.e. labor-inducing, effects of asoprisnil are blunted or absent. Studies in non-human primates played a key role during the preclinical development of selective progesterone receptor modulators. These studies provided the first evidence of uterus-selective effects of asoprisnil and structurally related compounds, and the rationale for clinical development of asoprisnil. [Abstract/Link to Full Text]

Hastings JM, Fazleabas AT
A baboon model for endometriosis: implications for fertility.
Reprod Biol Endocrinol. 2006 Oct 9;4 Suppl 1S7.
ABSTRACT : Endometriosis is one of the most common causes of chronic pelvic pain and infertility in women in the reproductive age group. Although the existence of this disease has been known for over 100 years our current knowledge of its pathogenesis and the pathophysiology of its related infertility remains unclear. Several reasons contribute to our lack of knowledge, the most critical being the difficulty in carrying out objective long-term studies in women. Thus, we and others have developed a model of this disease in the non-human primate, the baboon (Papio anubis). Intraperitoneal inoculation of autologous menstrual endometrium results in the development of endometriotic lesions with gross morphological characteristics similar to those seen in the human. Multiple factors have been implicated in endometriosis-associated infertility. We have described aberrant levels of factors involved in multiple pathways important in the establishment of pregnancy, in the endometrium of baboons induced with endometriosis. Specifically, we have observed dysregulation of proteins involved in invasion, angiogenesis, methylation, cell growth, immunomodulation, and steroid hormone action. These data suggest that, in an induced model of endometriosis in the baboon, an increased angiogenic capacity, decreased apoptotic potential, progesterone resistance, estrogen hyper-responsiveness, and an inability to respond appropriately to embryonic signals contribute to the reduced fecundity associated with this disease. [Abstract/Link to Full Text]

Slayden OD, Brenner RM
A critical period of progesterone withdrawal precedes menstruation in macaques.
Reprod Biol Endocrinol. 2006 Oct 9;4 Suppl 1S6.
ABSTRACT : Macaques are menstruating nonhuman primates that provide important animal models for studies of hormonal regulation in the uterus. In women and macaques the decline of progesterone (P) at the end of the cycle triggers endometrial expression of a variety of matrix metalloproteinase (MMP) enzymes that participate in tissue breakdown and menstrual sloughing. To determine the minimal duration of P withdrawal required to induce menses, we assessed the effects of adding P back at various time points after P withdrawal on both frank bleeding patterns and endometrial MMP expression. Artificial menstrual cycles were induced by treating the animals sequentially with implants releasing estradiol (E2) and progesterone (P). To assess bleeding patterns, P implants were removed at the end of a cycle and then added back at 12, 24, 30, 36, 40, 48, 60, or 72 hours (h) after the initial P withdrawal. Observational analysis of frank bleeding patterns showed that P replacement at 12 and 24 h blocked menses, replacement at 36 h reduced menses but replacement after 36 h failed to block menses. These data indicate that in macaques, a critical period of P withdrawal exists and lasts approximately 36 h. In other similarly cycled animals, we withdrew P and then added P back either during (12-24 h) or after (48 h) the critical period, removed the uterus 24 h after P add back and evaluated endometrial MMP expression. Immunocytochemistry showed that replacement of P during the critical period suppressed MMP-1, -2 and -3 expression along with menses, but replacement of P at 48 h, which failed to suppress mense, suppressed MMP-1 and MMP-3 but did not block MMP-2. We concluded that upregulation of MMPs is essential to menses induction, but that after the critical period, menses will occur even if some MMPs are experimentally blocked. [Abstract/Link to Full Text]

Critchley HO, Kelly RW, Baird DT, Brenner RM
Regulation of human endometrial function: mechanisms relevant to uterine bleeding.
Reprod Biol Endocrinol. 2006 Oct 9;4 Suppl 1S5.
ABSTRACT : This review focuses on the complex events that occur in the endometrium after progesterone is withdrawn (or blocked) and menstrual bleeding ensues. A detailed understanding of these local mechanisms will enhance our knowledge of disturbed endometrial/uterine function - including problems with excessively heavy menstrual bleeding, endometriosis and breakthrough bleeding with progestin only contraception. The development of novel strategies to manage these clinically significant problems depends on such new understanding as does the development of new contraceptives which avoid the endometrial side effect of breakthrough bleeding. [Abstract/Link to Full Text]

Giudice LC
Application of functional genomics to primate endometrium: insights into biological processes.
Reprod Biol Endocrinol. 2006 Oct 9;4 Suppl 1S4.
ABSTRACT : Endometrium is a dynamic tissue that responds on a cyclic basis to circulating levels of the ovarian-derived steroid hormones, estradiol and progesterone. Functional genomics has enabled a global approach to understanding gene regulation in whole endometrial tissue in the setting of a changing hormonal milieu. The proliferative phase of the cycle, under the influence of estradiol, has a preponderance of genes involved in DNA synthesis and cell cycle regulation. Interestingly, genes encoding ion channels and cell adhesion, as well as angiogenic factors, are also highly regulated in this phase of the cycle. After the LH surge, different gene expression profiles are uniquely observed in the early secretory, mid-secretory (window of implantation), and late secretory phases. The early secretory phase is notable for up-regulation of multiple genes and gene families involved in cellular metabolism, steroid hormone metabolism, as well as some secreted glycoproteins. The mid-secretory phase is characterized by multiple biological processes, including up-regulation of genes encoding secreted glycoproteins, immune response genes with a focus on innate immunity, and genes involved in detoxification mechanisms. In the late secretory phase, as the tissue prepares for desquamation, there is a marked up-regulation of an inflammatory response, along with matrix degrading enzymes, and genes involved in hemostasis, among others. This monograph reviews hormonal regulation of gene expression in this tissue and the molecular events occurring therein throughout the cycle derived from functional genomics analysis. It also highlights challenges encountered in using human endometrial tissue in translational research in this context. [Abstract/Link to Full Text]

Okulicz WC
Cellular and molecular regulation of the primate endometrium: a perspective.
Reprod Biol Endocrinol. 2006 Oct 9;4 Suppl 1S3.
ABSTRACT : This contribution will trace some of the many seminal studies on the female uterus (endometrium) over the centuries and conclude with a description of some current research initiatives in our laboratory. Numerous contributions from many investigators over the years have contributed to our current understanding of endometrial function. The historical section of this chapter is intended to be a brief overall description of some of these efforts and not exhaustive. Additional information can be found in the review articles and books cited herein. [Abstract/Link to Full Text]