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[See also CRF and Unipolar Depression.] Peeters
F, Nicolson NA, Berkhof J. Levels and variability of daily life cortisol
secretion in major depression. Psychiatry Res. 2004 Apr
15;126(1):1-13. "Dysregulation of the hypothalamic-pituitary-adrenal (HPA)
axis is an important feature of major depressive disorder (MDD), but relatively
little attention has been given to within-person variability of hormone secretion
over time. Because most studies have been conducted in hospital settings, little
information is available about naturally occurring patterns of cortisol secretion
throughout the day in depressed outpatients. Multiple salivary cortisol samples
were obtained over a 6-day period from 47 outpatients with MDD and 39 healthy
controls in their everyday environment. We used multilevel regression analysis
to estimate the effects of MDD and associated clinical characteristics on cortisol
levels and intraindividual variability. Although more severe symptoms were associated
with small elevations in cortisol levels, we found no clear evidence for hypercortisolism
in the MDD group as a whole. However, cortisol output in MDD outpatients was less
stable from sample to sample, as evidenced by a significantly lower autocorrelation
than that observed in controls. Secretory patterns were particularly erratic in
patients with more severe or recurrent episodes. Findings suggest that erratic
cortisol secretion may be a more characteristic feature of HPA axis dysregulation
in MDD than hypercortisolism, especially in outpatient populations." [Abstract] Raison,
Charles L., Miller, Andrew H. When Not Enough Is Too Much: The Role
of Insufficient Glucocorticoid Signaling in the Pathophysiology of Stress-Related
Disorders Am J Psychiatry 2003 160: 1554-1565 "OBJECTIVE:
Previous theories have emphasized the role of excessive glucocorticoid activity
in the pathology of chronic stress. Nevertheless, insufficient glucocorticoid
signaling (resulting from decreased hormone bioavailability or reduced hormone
sensitivity) may have equally devastating effects on bodily function. Such effects
may be related in part to the role of glucocorticoids in restraining activation
of the immune system and other components of the stress response, including the
sympathetic nervous system (SNS) and corticotropin-releasing hormone (CRH). METHOD:
The literature on neuroendocrine function and glucocorticoid-relevant pathologies
in stress-related neuropsychiatric disorders, including posttraumatic stress disorder
and major depression, was reviewed. RESULTS: Although not occurring together,
both hypocortisolism and reduced responsiveness to glucocorticoids (as determined
by dexamethasone challenge tests) were reliably found. Stress-related neuropsychiatric
disorders were also associated with immune system activation/inflammation, high
SNS tone, and CRH hypersecretion, which are all consistent with insufficient glucocorticoid-mediated
regulation of stress hyperresponsiveness. Finally, antidepressants, a mainstay
in the treatment of stress-related disorders, were regularly associated with evidence
of enhanced glucocorticoid signaling. CONCLUSIONS: Neuroendocrine data provide
evidence of insufficient glucocorticoid signaling in stress-related neuropsychiatric
disorders. Impaired feedback regulation of relevant stress responses, especially
immune activation/inflammation, may, in turn, contribute to stress-related pathology,
including alterations in behavior, insulin sensitivity, bone metabolism, and acquired
immune responses. From an evolutionary perspective, reduced glucocorticoid signaling,
whether achieved at the level of the hormone or its receptor, may foster immune
readiness and increase arousal. Emphasis on insufficient glucocorticoid signaling
in stress-related pathology encourages development of therapeutic strategies to
enhance glucocorticoid signaling pathways." [Abstract]
Pariante
CM, Miller AH.
Glucocorticoid receptors in major depression: relevance
to pathophysiology and treatment.
Biol Psychiatry 2001 Mar
1;49(5):391-404
"Hyperactivity of the hypothalamic--pituitary--adrenal
(HPA) axis has been reliably observed in patients with major depression. One of
the primary features of this HPA axis hyperactivity is reduced sensitivity to
the inhibitory effects of the glucocorticoid dexamethasone on the production of
adrenocorticotropic hormone and cortisol during the dexamethasone suppression
test and, more recently, the dexamethasone--corticotropin-releasing hormone test.
Because the effects of glucocorticoids are mediated by intracellular receptors
including, most notably, the glucocorticoid receptor (GR), a number of studies
have considered the possibility that the number and/or function of GRs are reduced
in depressed patients. Moreover, whether antidepressants act by reversing these
putative GR changes has been examined. The extant literature on GR receptors in
major depression was reviewed along with studies examining the impact of antidepressants
on the GR. The data support the hypothesis that the function of the GR is reduced
in major depression in the absence of clear evidence of decreased GR expression.
The data also indicate that some antidepressants have direct effects on the GR,
leading to enhanced GR function and increased GR expression. Hypotheses regarding
the mechanism of these receptor changes involve relevant second messenger pathways
that regulate GR function. The findings indicate that the GR is an important molecular
target in major depression. Further elucidation of the biochemical and molecular
mechanisms involved in GR changes in major depression is an exciting frontier
that will no doubt lead to new insights into the pathophysiology and treatment
of affective disorders." [Abstract]
Webster
MJ, Knable MB, O'Grady J, Orthmann J, Weickert CS. Regional specificity
of brain glucocorticoid receptor mRNA alterations in subjects with schizophrenia
and mood disorders. Mol Psychiatry 2002;7(9):985-94, 924 "Glucocorticoid
receptors (GR) mediate the direct effects of glucocorticoids released in response
to stress and the regulation of the hypothalamic-pituitary-adrenocortical (HPA)
system through a negative feedback mechanism. Individuals with major mental illness,
who often exhibit hypercortisolemia, may have down-regulated levels of GR mRNA.
In situ hybridization for GR mRNA was performed on post-mortem specimens from
patients suffering from depression, bipolar disorder, schizophrenia and from normal
controls (n = 15 per group). In frontal cortex, GR mRNA levels were decreased
in layers III-VI in the subjects with depression and schizophrenia. In inferior
temporal cortex, GR mRNA levels were decreased in layer IV in all three diagnostic
groups. In the entorhinal cortex, GR mRNA levels were decreased in layers III
and VI in the bipolar group. In hippocampus, GR mRNA levels were reduced in the
dentate gyrus, CA(4), CA(3) and CA(1) in the schizophrenia group. In the subiculum,
GR mRNA levels were reduced in the bipolar group. These results suggest that GR
dysregulation occurs in all three major psychiatric illnesses with variability
according to anatomical site. The severity and heterogeneity of this reduction
may underlie some of the clinical heterogeneity seen in these disorders."
[Abstract] Kling
MA, Whitfield HJ Jr, Brandt HA, Demitrack MA, Kalogeras K, Geracioti TD, Perini
GI, Calabrese JR, Chrousos GP, Gold PW. Effects of glucocorticoid
antagonism with RU 486 on pituitary-adrenal function in patients with major depression:
time-dependent enhancement of plasma ACTH secretion. Psychopharmacol
Bull 1989;25(3):466-72 "Data from our group and others suggest that pituitary-adrenal
activation in major depression reflects a defect at or above the hypothalamus
which results in the hypersecretion of corticotropin-releasing hormone (CRH);
some have suggested, however, that elevated indices of cortisol secretion and
lack of suppressibility to dexamethasone may be a manifestation of a primary defect
in glucocorticoid receptor activation. We report here a study of early morning
pituitary-adrenal responses to the glucocorticoid antagonist RU 486 in patients
with major depression and healthy volunteers. Previous data suggested that the
response to RU 486 could represent an index of endogenous CRH secretory activity.
RU 486 produced a robust increase in plasma corticotropin (ACTH) and cortisol
secretion in both control subjects and depressed patients. In the controls, however,
the increase was confined to the last 2 hours of sampling (6 to 8 am), whereas
in the depressed patients the increase occurred throughout the sampling period
(3 to 8 am). The ACTH response in the depressed patients exceeded that in the
controls during most of the sampling period, including a significant (p less than
.005) increase between 3 and 4:30 am. These results are compatible with the idea
that hypercortisolism in major depression represents an alteration in the overall
set point for hypothalamic CRH secretion rather than a primary alteration at the
level of the glucocorticoid receptor." [Abstract]
Holsboer
F. Stress, hypercortisolism and corticosteroid receptors in depression:
implications for therapy. J Affect Disord 2001 Jan;62(1-2):77-91 "Clinical
and preclinical studies have gathered substantial evidence that alterations of
the stress hormone system play a major, causal role in the development of depression.
In this review article, a summary of studies sustaining that view is given and
data are presented which demonstrate that depression is associated with an impairment
of corticosteroid receptor function that gives rise to an excessive release of
neurohormones to which a number of signs and symptoms characteristic of depression
can be attributed. The studies referred to in the following unanimously support
the concept of an antidepressant mechanism of action that exerts its effects beyond
the cell membrane receptors of biogenic amines and particularly includes the improvement
of corticosteroid receptor function. When activated by ligands, corticosteroid
receptors act as transcription factors in correspondence with numerous other transcription
factors already known to be activated by antidepressants. Furthermore, the potential
of drugs that interfere more directly with stress hormone regulation, such as
corticosteroid receptor antagonists and corticotropin-releasing hormone receptor
antagonists, is discussed." [Abstract] Holsboer
F. The corticosteroid receptor hypothesis of depression. Neuropsychopharmacology
2000 Nov;23(5):477-501 "Signs and symptoms that are characteristic for
depression include changes in the setpoint of the hypothalamic-pituitary-adrenocortical
(HPA) system, which in the majority of these patients result in altered regulation
of corticotropin (ACTH) and cortisol secretory activity. More refined analysis
of the HPA system revealed that corticosteroid receptor (CR) signaling is impaired
in major depression, resulting among other changes, in increased production and
secretion of corticotropin-releasing hormone (CRH, also frequently abbreviated
CRF) in various brain regions postulated to be involved in the causality of depression.
This article summarizes the clinical and preclinical data, supporting the concept
that impaired CR signaling is a key mechanism in the pathogenesis of depression.
Mouse genetics, allowing for selective inactivation of genes relevant for HPA
regulation and molecular pharmacology, dissecting the intracellular cascade of
CR signaling, are the most promising future research fields, suited for identifying
genes predisposing to depression. Focusing on these two research lines may also
allow to gain insight into understanding how current antidepressants work and
further, how more specific targets for future antidepressant drugs can be identified."
[Abstract] Hugin-Flores
ME, Steimer T, Schulz P, Vallotton MB, Aubert ML. Chronic corticotropin-releasing
hormone and vasopressin regulate corticosteroid receptors in rat hippocampus and
anterior pituitary. Brain Res 2003 Jun 27;976(2):159-170 "Corticotropin-releasing
hormone (CRH) and vasopressin (AVP) participate in the endocrine, autonomic, immunological
and behavioral response to stress. CRH and AVP receptors are found in hippocampus
and anterior pituitary, where mineralocorticoid (MR) and glucocorticoid (GR) receptors
are abundant. We investigated the possible influence of CRH and AVP on the regulation
of MR and GR in both tissues. CRH, AVP, or their antagonists were administered
to adrenalectomized rats substituted with corticosterone, to avoid interference
with adrenal secretion. Repeated i.c.v. oCRH injections (10 &mgr;g) for 5
days significantly decreased MR and GR mRNA in hippocampus and MR mRNA in anterior
pituitary. AVP significantly increased both corticosteroid receptor mRNAs, as
repeated i.c.v. injections (5 &mgr;g) for 5 days in hippocampus, and as continuous
i.c.v. infusion (10 ng/h/5 days) in anterior pituitary. The i.c.v. infusion of
5 or 10 &mgr;g/day of the alpha-helical CRH antagonist during intermittent
restraint stress (5 days), induced a significant decrease in hippocampal MR binding.
In anterior pituitary, 5 &mgr;g/day significantly decreased MR binding, while
10 &mgr;g/day significantly increased GR binding. Under the same conditions
of stress, the infusion of 15 &mgr;g/day of the vasopressin V1a/1b receptor
antagonist [dP Tyr (Me)(2)AVP] significantly increased MR and GR binding in hippocampus
and anterior pituitary; 5 &mgr;g/day significantly decreased pituitary MR
binding. Our results show that CRH and AVP regulate MR and GR in hippocampus and
anterior pituitary. This reveals another important function of CRH and AVP, which
could be relevant to understand stress adaptation and the pathophysiology of stress-related
disorders like major depression." [Abstract]
van
Haarst AD, Oitzl MS, Workel JO, de Kloet ER. Chronic brain glucocorticoid
receptor blockade enhances the rise in circadian and stress-induced pituitary-adrenal
activity. Endocrinology 1996 Nov;137(11):4935-43 "This
study examined the hypothesis that experimentally induced corticosteroid resistance
in the brain would lead to adaptations in the activity of the hypothalamic-pituitary-adrenal
(HPA) axis similar to the endocrine features of the endogenous resistance accompanying
the pathogenesis of depression. For this purpose, the glucocorticoid antagonist
RU 38486 (aGC) was infused intracerebroventricularly (i.c.v.) (100 ng/h) via Alzet
minipumps for several days. During this chronic receptor blockade, parameters
for basal and stress-induced HPA activity were measured in a longitudinal study
design. Chronic i.c.v. infusion of the aGC did not affect basal morning levels
of ACTH and corticosterone. During the afternoon phase of the circadian cycle,
the aGC caused gradual and sequential changes in the HPA axis. After aGC infusion,
the circadian rise of ACTH levels was enhanced in the afternoon of day 1, but
was normal on subsequent days. For corticosterone, basal afternoon levels towards
the diurnal peak were increased at days 1, 3, and 4 in aGC-treated rats. On day
2, in contrast, corticosterone levels did not differ from vehicle-infused controls.
Paraventricular CRH messenger RNA, as measured at day 4, was not altered by aGC
treatment. After 10 days of aGC treatment, the adrenal weight was increased, and
the sensitivity of adrenocortical cells in vitro to ACTH was enhanced. Corticosteroid
receptor binding in vitro in hippocampus, hypothalamus, and pituitary was not
different between the aGC and vehicle-treated rats. In a second series of experiments,
the HPA responsiveness to the stress of a novel environment at day 2 in the morning
was increased after chronic aGC infusion, at a time basal hormone levels were
not affected. The data show that 1) chronic i.c.v. infusion of aGC readily enhances
the amplitude of circadian corticosterone changes, presumably by increasing the
adrenocortical sensitivity to ACTH; 2) chronic aGC-treated animals show an enhanced
ACTH and corticosterone response to stress, which is delayed in termination; 3)
corticosteroid receptor expression, basal CRH messenger RNA, and ACTH levels are
not altered after prolonged chronic aGC treatment. It is concluded that, over
a period of a few days, aGC-induced corticosteroid resistance triggers a sequelae
of pituitary-adrenal adaptations ultimately resulting in hypercorticism. Paradoxically,
however, this hypercorticism develops because of increased peak levels of corticosteroid
hormone rather than through elevated trough levels as is commonly observed during
depressive illness." [Abstract] Dijkstra,
Ivar, Tilders, Fred J. H., Aguilera, Greti, Kiss, Alexander, Rabadan-Diehl, Cristina,
Barden, Nicholas, Karanth, Sharada, Holsboer, Florian, Reul, Johannes M. H. M. Reduced
Activity of Hypothalamic Corticotropin-Releasing Hormone Neurons in Transgenic
Mice with Impaired Glucocorticoid Receptor Function J. Neurosci.
1998 18: 3909-3918 "Loss of central glucocorticoid receptor (GR) function
is thought to be involved in the development of neuroendocrine and psychiatric
disorders associated with corticotropin-releasing hormone (CRH) hyperactivity.
The possible causal relationship between defective GR function and altered activity
of CRH neurons was studied in transgenic mice (TG) expressing antisense RNA against
GR. Immunocytochemical studies showed significant reductions in CRH immunoreactive
neurons in the paraventricular nucleus (PVN) and in CRH and vasopressin (AVP)
stores in the external zone of the median eminence. Concomitantly, stimulus-evoked
CRH secretion from mediobasal hypothalami of TG mice in vitro was reduced significantly.
However, CRH mRNA levels in the PVN of TG mice were marginally lower than those
in wild-type (WT) mice. 125I-CRH binding autoradiography revealed no differences
between WT and TG animals in any of the brain regions that were studied. Basal
plasma corticosterone (cort) levels and 125I-CRH binding, CRH-R1 mRNA, POMC mRNA,
and POMC hnRNA levels in the anterior pituitary gland were similar in WT and TG
mice. Intraperitoneal injection of interleukin-1beta (IL-1beta) increased plasma
cort levels, CRH mRNA in the PVN, and anterior pituitary POMC hnRNA similarly
in WT and TG mice. The injection of saline significantly reduced anterior pituitary
CRH-R1 mRNA levels in WT mice, but not in TG mice, whereas IL-1beta produced a
decrease in these mRNA levels in both strains. The data show that long-term GR
dysfunction can be associated with reduced activity of CRH neurons in the PVN
and decreased sensitivity of pituitary CRH-R1 mRNA to stimulus-induced downregulation.
Moreover, the hypothalamic changes observed in this model suggest that impaired
GR function, at least if present since early embryonic life, does not necessarily
result in CRH hyperexpression characteristics of disorders such as major depression."
[Full Text] Sharada
Karanth, Astrid C. E. Linthorst, Günther K. Stalla, Nicholas Barden, Florian
Holsboer, and Johannes M. H. M. Reul Hypothalamic-Pituitary-Adrenocortical
Axis Changes in a Transgenic Mouse with Impaired Glucocorticoid Receptor Function
Endocrinology 138: 3476-3485 "Recently, a transgenic
mouse with impaired glucocorticoid receptor (GR) function was created to serve
as an animal model for the study of neuroendocrine changes occurring in stress-related
disorders, such as major depression. Here, we investigated the hypothalamic-pituitary-adrenocortical
(HPA) axis changes in these transgenic mice. There were no significant differences
between basal early morning plasma ACTH and corticosterone levels in normal and
transgenic mice. When animals were exposed to a mild stressor, an enhanced response
in plasma ACTH was observed in the transgenic mice, whereas plasma corticosterone
responses were not different. In view of these differences in plasma ACTH and
corticosterone responses, we directed our studies toward the regulation of ACTH
secretion on the hypothalamic-hypophyseal level in vitro. Therefore, an in vitro
model, the pituitary-hypothalamic complex (PHc) was developed and its ACTH release
profile was compared with that of the pituitary (PI) alone. The basal ACTH release
by PHc and PI from normal and transgenic mice was similar. Regardless of the strain
under study, the basal ACTH release by PI was significantly lower than the release
by PHc. Stimulation of tissues with either high K+ (56 mM) or CRH (10 or 20 nM)
produced an enhanced ACTH release from both PHc and PI, whereas the response in
PI was larger than that in PHC. Moreover, the responses to these stimuli were
markedly enhanced in tissues from transgenic mice. In tissues of normal mice,
corticosterone inhibited both basal and CRH-stimulated ACTH release more potently
in PHc than in PI. Furthermore, the feedback capacity of corticosterone to restrain
both basal and CRH-stimulated ACTH release was highly impaired in tissues of transgenic
mice, whereas the feedback in PHc appeared to be more affected than that in the
PI of these animals. In conclusion, the in vitro
data on PHc and PI revealed intrahypothalamic mechanisms operating 1) to fine-tune
stimulus-evoked ACTH responses; and 2) to facilitate the negative feedback action
of glucocorticoids. Moreover, in the transgenic tissues, the impaired GR function
was found to cause augmented stimulus-evoked ACTH responses and an impaired glucocorticoid
feedback efficacy which appeared to be mainly defective at the hypothalamic level.
Thus, in the transgenic mice with life-long central GR dysfunction we found impaired
negative feedback combined with "normal" (i.e. noncompensated) in vivo
plasma corticosterone responses. This is a condition with potentially grave pathophysiological
consequences and, therefore, this transgenic animal may be regarded as a valuable
model for the study of functional glucocorticoid insufficiency at the central
nervous system level." [Full
Text] Heuser I. Anna-Monika-Prize
paper. The hypothalamic-pituitary-adrenal system in depression. Pharmacopsychiatry
1998 Jan;31(1):10-3 "Patients with depression frequently have symptom
clusters which point strongly to involvement of the hypothalamic-pituitary-adrenal
(HPA) system as a relay station between neurocircuitries in the brain and peripheral
hormone and autonomic nervous function. It has been proposed that this increased,
state-dependent hyperactivity of the HPA-system in depression is probably initiated
and/or maintained by the combination of enhanced central production of CRH and
desensitization of the binary, glucocorticoid receptor binding system in the hippocampus,
which is the central regulator of HPA system activity. In a first series of studies
a refined neuroendocrine test to probe the integrity of HPA system status--the
combined dexamethasone suppression/CRH challenge (DEX/CRH) test--was developed
and the differential effects of aging and depressed psychopathology on DEX/CRH
test outcome were described. In a second set of studies, the chronological relationship
between improvement of psychopathology in depressed patients treated with antidepressants
and normalization of the disturbed HPA system function in these patients was further
elucidated. Given the evidence from animal studies, we conclude that antidepressants
induce an up-regulation of hippocampal glucocorticoid receptor mRNA concentration,
thus amplifying the negative feedback effect of glucocorticoids. This then results
in the normalization of DEX/CRH test results observed in the depressed patients
in our study. We further conclude that dampening of HPA system hyperactivity in
depression by means of antidepressants is a conditio sine qua non for successful
improvement of psychopathology." [Abstract] Montkowski
A, Barden N, Wotjak C, Stec I, Ganster J, Meaney M, Engelmann M, Reul JM, Landgraf
R, Holsboer F. Long-term antidepressant treatment reduces behavioural
deficits in transgenic mice with impaired glucocorticoid receptor function.
J Neuroendocrinol 1995 Nov;7(11):841-5 "Impaired cognitive function and
enhanced activity of the hypothalamic-pituitary-adrenocortical system are among
the cardinal symptoms of major depression in humans that resolve after successful
antidepressant treatment. We used a transgenic mouse model expressing antisense
RNA complementary to that of glucocorticoid receptor (GR) mRNA to test the hypothesis
that reduced GR function can cause these clinical disturbances. The transgenic
mice show profound behavioural changes in a number of animal tests that are indicative
of cognitive impairment. These mice also have elevated plasma corticotropin concentrations
in response to stress. After long-term treatment with moclobemide, a reversible
inhibitor of monoamine oxidase type A that acts clinically as an antidepressant,
both the behavioural deficits and the hormonal alterations disappeared. These
observations suggest that a transgenic mouse with GR dysfunction may be a useful
model for investigation of drug effects on the cognitive and neuroendocrine aspects
of depression." [Abstract]
Pepin MC, Pothier F, Barden N. Antidepressant
drug action in a transgenic mouse model of the endocrine changes seen in depression. Mol
Pharmacol 1992 Dec;42(6):991-5 "We have created transgenic mouse lines
with impaired glucocorticoid receptor function by expression of a type II glucocorticoid
receptor antisense RNA in brain tissues. These animals have endocrinological characteristics
similar to those seen in depression, including a hyperactive hypothalamic-pituitary-adrenal
axis as indicated by elevated plasma corticosterone and adrenocorticotropin hormone
levels. Treatment of transgenic animals with the tricyclic antidepressant desipramine
increased hypothalamic glucocorticoid receptor mRNA concentration and dexamethasone-binding
activity while decreasing plasma adrenocorticotropin hormone concentration and
corticosterone levels. These results support the hypothesis that antidepressants
exert action on the hypothalamic-pituitary-adrenal axis through modulation of
glucocorticoid receptor gene expression." [Abstract] Barden
N. Regulation of corticosteroid receptor gene expression in depression
and antidepressant action. J Psychiatry Neurosci 1999 Jan;24(1):25-39 "OBJECTIVE:
Major alterations of the hypothalamic-pituitary-adrenocortical (HPA) system are
often seen in patients with depression, and can be reversed by successful antidepressant
therapy. Persuasive evidence points to the involvement of a dysfunctional glucocorticoid
receptor system in these changes. The authors developed a transgenic mouse to
determine the mechanism for these changes. DESIGN: In vivo and in vitro animal
experiments. ANIMALS: Transgenic mice expressing glucocorticoid receptor antisense
RNA and control mice. INTERVENTIONS: In vivo: hormone assays and dexamethasone
suppression tests; in vitro: cell transfection, chloramphenicol acetyl transferase
assay, Northern blot analysis, binding assays of cytosolic receptor. OUTCOME MEASURES:
Indicators of depressive disorder in transgenic mice, effect of antidepressant
therapy on dexamethasone binding in transgenic mouse hippocampus, mouse behaviour,
and glucocorticoid receptor activity. RESULTS: Transgenic mice showed no suppression
of corticosterone with a dose of 2 mg per 100 g body weight dexamethasone. Treatment
with amitriptyline reduced levels of corticotropin and corticosterone, increased
glucocorticoid receptor mRNA concentrations and glucocorticoid binding capacity
of several brain areas, and reversed behavioural changes. In vitro experiments
also showed that desipramine increased glucocorticoid receptor mRNA. CONCLUSION:
These transgenic mice have numerous neuroendocrine characteristics of human depression
as well as altered behaviour. Many of these neuroendocrinologic and behavioural
characteristics are reversed by antidepressants. The antidepressant-induced increase
in glucocorticoid receptor activity may render the HPA axis more sensitive to
glucocorticoid feedback. This new insight into antidepressant drug action suggests
a novel approach to the development of new antidepressant drugs." [Abstract]
Okugawa
G, Omori K, Suzukawa J, Fujiseki Y, Kinoshita T, Inagaki C. Long-term
treatment with antidepressants increases glucocorticoid receptor binding and gene
expression in cultured rat hippocampal neurones. J Neuroendocrinol
1999 Nov;11(11):887-95 "Since the glucocorticoid receptor (GR) and/or
mineralocorticoid receptor (MR) in the hippocampus have been implicated in cortisol
feedback of the hypothalamus-pituitary-adrenal (HPA) axis, abnormalities in those
receptors might underlie the hyperactivity of the HPA axis described in patients
with major depression. Animal studies have shown that long-term in-vivo treatment
with antidepressants up-regulates hippocampal GR and/or MR, but it is not clear
whether this up-regulation is evoked through a direct action of antidepressants
on these receptors. We therefore examined the direct effects of long-term antidepressant
treatment on GR binding and the levels of GR messenger RNA (mRNA) in primary cultures
of rat hippocampal neurones. The time course of the effects of the tricyclic antidepressants
desipramine and amitriptyline on GR binding, as assessed by [3H]dexamethasone
binding using RU 28362, a specific agonist for GR, showed a biphasic mode of stimulation:
desipramine significantly increased the GR binding with 2-day exposure by 36%
over that in controls and by 99% and 60% with 10- and 14-day exposures, respectively.
Amitriptyline also led to a significant increase in GR binding, with peaks at
2 (by 60%) and 14 days of exposure (by 60%). The effects of 14-day treatment with
desipramine required at least the first 4-day exposure, and the first 10-day exposure
was required for the full effect. Northern blot analysis demonstrated that the
GR mRNA level was significantly increased by 14-day treatment with desipramine
(+142% over control), amitriptyline (+108%), mianserin (+124%), paroxetine (+42%)
and sulpiride (+92%), but not with haloperidol. Immunocytochemistry for GR revealed
that 2- or 14-day treatment with desipramine significantly increased the number
of GR-positive cells with dominant immunoreactivity in the nuclei of granule cell-like
neurones or in perikarya of pyramidal cell- and granule cell-like neurones. These
findings suggest that tricyclic antidepressants directly increase hippocampal
GR by short-term (2-day) and long-term (14-day) exposure, and that the increase
by long-term exposure is evoked commonly with different classes of antidepressants
through transcriptional up-regulation of GR expression." [Abstract]
Brady LS, Gold PW, Herkenham M, Lynn AB, Whitfield
HJ Jr. The antidepressants fluoxetine, idazoxan and phenelzine alter
corticotropin-releasing hormone and tyrosine hydroxylase mRNA levels in rat brain:
therapeutic implications. Brain Res 1992 Feb 14;572(1-2):117-25 "Various
classes of antidepressant drugs with distinct pharmacologic actions are differentially
effective in the treatment of classic melancholic depression--characterized by
pathological hyperarousal and atypical depression--associated with lethargy, hypersomnia,
and hyperphagia. All antidepressant agents exert their therapeutic efficacy only
after prolonged administration. In situ hybridization histochemistry was used
to examine in rats the effects of short-term (2 weeks) and long-term (8 weeks)
administration of 3 different classes of activating antidepressant drugs which
tend to be preferentially effective in treating atypical depressions, on the expression
of central nervous system genes thought to be dysregulated in major depression.
Daily administration (5 mg/kg, i.p.) of the selective 5-hydroxytryptophan (5-HT)
reuptake inhibitor fluoxetine, the selective alpha 2-adrenergic receptor antagonist
idazoxan, and the nonspecific monoamine oxidase A and B inhibitor phenelzine increased
tyrosine hydroxylase mRNA levels by 70-150% in the locus coeruleus after 2 weeks
of drug and by 71-115% after 8 weeks. The 3 drugs decreased corticotropin-releasing
hormone mRNA levels by 30-48% in the paraventricular nucleus of the hypothalamus.
The decreases occurred at 8 weeks but not at 2 weeks. No consistent change in
steroid hormone receptor mRNA levels was seen in the hippocampus with the 3 drugs,
but fluoxetine and idazoxan increased the level of mineralocorticoid receptor
(MR) and glucocorticoid receptor (GR) mRNA, respectively, after 8 weeks of drug
administration. Proopiomelanocortin (POMC) mRNA levels in the anterior pituitary
and plasma adrenocorticotropic-hormone (ACTH) levels were not altered after 2
or 8 weeks of drug treatment." [Abstract]
Brady LS, Whitfield HJ Jr, Fox RJ, Gold PW, Herkenham M. Long-term
antidepressant administration alters corticotropin-releasing hormone, tyrosine
hydroxylase, and mineralocorticoid receptor gene expression in rat brain. Therapeutic
implications. J Clin Invest 1991 Mar;87(3):831-7 "Imipramine
is the prototypic tricyclic antidepressant utilized in the treatment of major
depression and exerts its therapeutic efficacy only after prolonged administration.
We report a study of the effects of short-term (2 wk) and long-term (8 wk) administration
of imipramine on the expression of central nervous system genes among those thought
to be dysregulated in imipramine-responsive major depression. As assessed by in
situ hybridization, 8 wk of daily imipramine treatment (5 mg/kg, i.p.) in rats
decreased corticotropin-releasing hormone (CRH) mRNA levels by 37% in the paraventricular
nucleus (PVN) of the hypothalamus and decreased tyrosine hydroxylase (TH) mRNA
levels by 40% in the locus coeruleus (LC). These changes were associated with
a 70% increase in mRNA levels of the hippocampal mineralocorticoid receptor (MR,
type I) that is thought to play an important role in mediating the negative feedback
effects of low levels of steroids on the hypothalamic-pituitary-adrenal (HPA)
axis. Imipramine also decreased proopiomelanocortin (POMC) mRNA levels by 38%
and glucocorticoid receptor (GR, type II) mRNA levels by 51% in the anterior pituitary.
With the exception of a 20% decrease in TH mRNA in the LC after 2 wk of imipramine
administration, none of these changes in gene expression were evident as a consequence
of short-term administration of the drug. In the light of data that major depression
is associated with an activation of brain CRH and LC-NE systems, the time-dependent
effect of long-term imipramine administration on decreasing the gene expression
of CRH in the hypothalamus and TH in the LC may be relevant to the therapeutic
efficacy of this agent in depression." [Abstract] Okuyama-Tamura
M, Mikuni M, Kojima I. Modulation of the human glucocorticoid receptor
function by antidepressive compounds. Neurosci Lett 2003
May 22;342(3):206-10 "Hyperactivity of the hypothalamic-pituitary-adrenal
axis is associated with depression. We investigated the effect of various types
of antidepressant agents in vitro on the function of glucocorticoid receptor (GR).
Desipramine, clomiplamine, fluoxetine, milnacipran and clorgyline all induced
rapid and sustained translocation of GR into the nucleus of human lymphocytes.
In contrast, major and minor tranquilizers, lithium and verapamil, a blocker of
membrane steroid transporter, were without effect. These antidepressants did not
affect GR-mediated transcription by themselves, but significantly inhibited dexamethasone-induced
transcription. These results indicate that structurally different antidepressants
induce translocation of GR and inhibit GR-mediated transcription." [Abstract] Carmine
M. Pariante, Andrew Makoff, Simon Lovestone, Susan Feroli, Alexandra Heyden, Andrew
H. Miller, and Robert W. Kerwin Antidepressants enhance glucocorticoid
receptor function in vitro by modulating the membrane steroid transporters Br
J Pharmacol 2001 134: 1335-1343 "1. Previous data demonstrate that the
tricyclic antidepressant, desipramine, induces glucocorticoid receptor (GR) translocation
from the cytoplasm to the nucleus in L929 cells and increases dexamethasone-induced
GR-mediated gene transcription in L929 cells stably transfected with the mouse
mammary tumour virus-chloramphenicol acetyltransferase (MMTV-CAT) reporter gene
(LMCAT cells) (Pariante et al., 1997). 2. To extend these findings, the present
study has investigated the effects of 24 h coincubation of LMCAT cells with dexamethasone
and amitriptyline, clomipramine, paroxetine, citalopram or fluoxetine. 3. All
antidepressants, except fluoxetine, enhanced GR-mediated gene transcription, with
clomipramine having the greatest effect (10 fold increase). Twenty-four hours
coincubation of cells with desipramine, clomipramine or paroxetine, also enhanced
GR function in the presence of cortisol, but not of corticosterone. 4. It is proposed
that these effects are due to the antidepressants inhibiting the L929 membrane
steroid transporter, which actively extrudes dexamethasone and cortisol from the
cell, but not corticosterone. This is further confirmed by the fact that clomipramine
failed to enhance GR-mediated gene transcription in the presence of dexamethasone
when the membrane steroid transporter was blocked by verapamil. 5. The membrane
steroid transporters that regulate access of glucocorticoids to the brain in vivo,
like the multiple drug resistance p-glycoprotein, could be a fundamental target
for antidepressant action." [Abstract] Rossby
SP, Nalepa I, Huang M, Perrin C, Burt AM, Schmidt DE, Gillespie DD, Sulser F. Norepinephrine-independent
regulation of GRII mRNA in vivo by a tricyclic antidepressant. Brain
Res 1995 Jul 31;687(1-2):79-82 "Desipramine (DMI), a tricyclic antidepressant
drug used in the treatment of depression, has been shown to increase steady-state
levels of glucocorticoid receptor type II (GRII) mRNA in vitro and in vivo. To
determine whether this effect is secondary to norepinephrine (NE) reuptake inhibition
i.e., increases in synaptic NE induced by DMI, GRII mRNA levels were assayed in
rat hippocampus following neurotoxic lesioning of NE neurons with DSP4. Chronic
DMI treatment significantly increased GRII mRNA levels to the same degree in lesioned
and non-lesioned animals. In contrast to DMI, the non-tricyclic antidepressant
fluoxetine had no effect on GRII mRNA. These results provide evidence which demonstrates
that a tricyclic antidepressant can regulate steady-state mRNA levels in vivo
by a mechanism which is independent of its effects on synaptic monoamine levels."
[Abstract]
Pariante,
Carmine M., Pearce, Bradley D., Pisell, Tracy L., Owens, Michael J., Miller, Andrew
H. Steroid-Independent Translocation of the Glucocorticoid Receptor
by the Antidepressant Desipramine Mol Pharmacol 1997 52:
571-581 "The glucocorticoid receptor (GR) is a ligand-regulated transcription
factor that in its unactivated form resides primarily in the cytoplasm. After
being bound by steroid, the GR undergoes a conformational change and translocates
to the nucleus, where it influences gene transcription. Because the GR mediates
negative feedback exerted by circulating glucocorticoid hormones on the hypothalamic-pituitary-adrenal
(HPA) axis, it has been hypothesized that abnormalities in GR expression and/or
function may underlie the HPA axis hyperactivity described in patients with major
depression. In further support of this hypothesis, animal studies have shown that
long term in vivo treatment with antidepressants enhances glucocorticoid feedback
inhibition, possibly through a direct effect on the GR. To examine this latter
possibility, we evaluated translocation of the GR from the cytoplasm to the nucleus
after 24-hr in vitro treatment of L929 cells (mouse fibroblasts) with the tricyclic
antidepressant desipramine (0.1-10 microM) in the presence or absence of the synthetic
steroid dexamethasone. In addition, GR-mediated gene transcription was measured
with the use of L929 cells stably transfected with the mouse mammary tumor virus-chloramphenicol
acetyltransferase reporter gene. Desipramine was found to (i) induce GR translocation
from the cytoplasm to the nucleus in the absence of steroids (with no effect alone
on GR-mediated gene transcription) and (ii) potentiate dexamethasone-induced GR
translocation and dexamethasone-induced GR-mediated gene transcription. Treatment
with desipramine for 24-96 hr had no effect on the expression of GR protein as
measured by cytosolic radioligand receptor binding. We suggest that one important
aspect of the effects of antidepressants in vivo may be to facilitate GR-mediated
feedback inhibition on the HPA axis, by facilitating GR translocation and function,
and thereby reverse glucocorticoid hypersecretion in depression." [Full
Text] | Hatzinger
M. Neuropeptides and the hypothalamic-pituitary-adrenocortical (HPA)
system: review of recent research strategies in depression. World
J Biol Psychiatry 2000 Apr;1(2):105-11 "Depressed patients show a variety
of alterations in hypothalamic-pituitary-adrenocortical (HPA) system regulation
which is reflected by increased pituitary-adrenocortical hormone secretion at
baseline and a number of aberrant neuroendocrine function tests. The latter include
the combined dexamethasone (DEX) suppression/corticotropin-releasing hormone (CRH)
challenge test, in which CRH was able to override DEX induced suppression of ACTH
and cortisol secretion. Whereas the abnormal HPA activation in these patients
improved in parallel with clinical remission, persistent HPA dysregulation was
associated with an increased risk of relapse. Moreover, healthy subjects at high
genetic risk for depression also showed this phenomenon as a trait marker. In
consequence, it has been concluded that HPA alteration and developmen as well
as course of depression may be causally related. As evidenced from clinical and
preclinical studies, underlying mechanisms of these abnormalities involve impairment
of central corticosteroid receptor function which leads to enhanced activity of
hypothalamic neurons synthesising and releasing vasopressin and CRH. These neuropeptides
mediate not only neuroendocrine but also behavioural effects. Recent research
provided evidence that CRH can induce depression-like symptoms in animals and
that these signs are mediated through the CRH1 receptor subtype. Hence, therapeutical
application of new compounds acting more specifically on the HPA system such as
CRH1 receptor antagonists appear to be a promising approach for future treatment
options of depression. In conclusion, research in neuroendocrinology provided
new insights into the underlying pathophysiology of depression and, in consequence,
may lead to the development of new therapeutic tools." [Abstract] Muller
M, Holsboer F, Keck ME. Genetic modification of corticosteroid receptor
signalling: novel insights into pathophysiology and treatment strategies of human
affective disorders. Neuropeptides 2002 Apr-Jun;36(2-3):117-31 "Every
disturbance of the body, either real or imagined, evokes a stress response. Essential
to this stress response is the activation of the hypothalamic-pituitary-adrenocortical
(HPA) system, finally resulting in the release of glucocorticoid hormones from
the adrenal cortex. Glucocorticoid hormones, in turn, feed back to this system
by central activation of two types of corticosteroid receptors: the glucocorticoid
receptor (GR) and the mineralocorticoid receptor (MR) which markedly differ in
their neuroanatomical distribution and ligand affinity. Whereas a brief period
of controllable stress, experienced with general arousal and excitement, can be
a challenge and might thus be beneficial, chronically elevated levels of circulating
corticosteroids are believed to enhance vulnerability to a variety of diseases,
including affective disorders. Corticosteroids are known to influence emotions
and cognitive processes, such as learning and memory. In addition, corticosteroids
play extremely important roles in modulating fear and anxiety-related behaviour.
The mechanisms by which corticosteroids exert their effects on behaviour are often
indirect, by modulating particular sets of neurons or neurotransmitter systems.
In addition, the timing of corticosteroid increase (before, during or after exposure
to a stressor) determines whether and how behaviour is affected.The cumulative
evidence makes a strong case implicating corticosteroid receptor dysfunction in
the pathogenesis of affective disorders. Although definitive controlled trials
remain to be conducted, there is evidence indicating that cortisol-lowering or
corticosteroid receptor antagonist treatments may be of clinical benefit in selected
individuals with major depression. A more detailed knowledge of the GR signalling
pathways therefore opens up the possibility to specifically target GR function.In
recent years, refined molecular technologies and the generation of genetically
engineered mice (e.g. "conventional" and "conditional" knock-outs)
have allowed to specifically target individual genes involved in corticosteroid
receptor signalling and stress hormone regulation. Given the fundamental role
of corticosteroid receptors in hippocampal integrity and mental performance during
aging and psychiatric disorders, the identification and detailed characterization
of these molecular pathways will ultimately lead to the development of novel neuropharmacological
intervention strategies." [Abstract]
Barden
N.
Modulation of glucocorticoid receptor gene expression by antidepressant
drugs.
Pharmacopsychiatry 1996 Jan;29(1):12-22
"Through
expression of a glucocorticoid receptor (GR) antisense RNA in brain, we have produced
transgenic mice with an hyperactive hypothalamic-pituitary-adrenocortical (HPA)
system similar to that seen in depressed patients. This model supports the hypothesis
that disturbed corticosteroid receptor regulation could be the primary factor
responsible for both the CRH/AVP hyperdrive that leads to increased activity of
the HPA system, and the premature escape from the cortisol suppressant action
of dexamethasone seen in affective disorders. Although normalisation of the hyperactive
HPA system occurs during successful antidepressant therapy of depressive illness,
these improvements do not correlate with changes in monoaminergic neurotransmitter
systems, suggesting that unknown mechanisms of action may be operative. Work from
my laboratory was the first to show that different types of antidepressants increased
glucocorticoid receptor (GR) mRNA. We found increased GR mRNA levels irrespective
of the preferential inhibitory action of antidepressant on the monoamine neurotransmitter
re-uptake and showed increased GR gene transcription in antidepressant-treated
mouse fibroblast cells that do not possess monoamine re-uptake mechanisms. We
measured changes in glucocorticoid response in cells transfected with a glucocorticoid-sensitive
reporter plasmid (MMTV-CAT) and observed increased glucocorticoid-stimulated CAT
activity when the cells were treated with antidepressant. A different chimaeric
gene construct consisting of a fragment of the GR gene promoter region fused to
the CAT gene allowed more direct measurement of antidepressant action and increased
CAT activity was also seen when cells transfected with this construct were treated
with antidepressant. Finally, GR mRNA concentration and glucocorticoid binding
activity were increased in brain tissues of animals chronically treated with antidepressant.
The time course of antidepressant actions on corticosteroid receptors coincides
with their long-term actions on HPA system activity and follows closely that of
clinical improvement of depression. This suggests that antidepressant-induced
changes in brain corticosteroid receptors may underlie the observed simultaneous
decrease in circulating ACTH and corticosterone levels and the decreased adrenal
size. Some of these effects may be mediated through CRH since, in antidepressant-treated
transgenic mice hypothalamic CRH mRNA levels were decreased. From this work we
have formulated the hypothesis that a primary action of antidepressants could
be the stimulation of corticosteroid receptor gene expression that renders the
HPA system more susceptible to feedback inhibition by cortisol. The resultant
decrease in HPA system activity could induce secondary changes in glucocorticoid-sensitive
gene expression and lead to redressment of neurotransmitter imbalance. This work
opens up a completely new insight into antidepressant drug action and suggests
a line of approach to the development of new drugs by focusing on this action."
[Abstract]
Post A, Ohl F, Almeida OF, Binder EB, Rucker M, Welt S, Binder E, Holsboer F, Sillaber I.
Identification of molecules potentially involved in mediating the in vivo actions of the corticotropin-releasing hormone receptor 1 antagonist, NBI30775 (R121919).
Psychopharmacology (Berl). 2005 Jan 29; [Epub ahead of print]
RATIONALE: The neuropeptide corticotropin-releasing hormone (CRH) plays a central role in the regulation of the hypothalamo-pituitary-adrenocortical (HPA) axis. The view that CRH hypersecretion underlies anxiety and mood disorders was recently supported by preclinical and clinical data obtained after application of the CRH receptor (CRH-R1) antagonist NBI30775 (R121919). Despite its therapeutic efficacy, there is only little information about its mechanisms of action on cellular and molecular targets. OBJECTIVE: To identify some of the intracellular substrates mediating the actions of NBI30775 after its acute administration in a stress-independent animal model. RESULTS: Of the different doses of NBI30775 tested (0.5, 1, 5 and 30 mg/kg), the 1-mg/kg dose proved behaviorally active insofar that it reduced anxiety-like behavior in mice under basal conditions. Subsequent analysis of brain tissues revealed NBI30775-induced increases in the nuclear translocation of glucocorticoid receptors (GR) and BAG-1, an upregulation of mRNA transcripts encoding GR, mineralocorticoid receptors (MR) and CRH-R1, and a suppression of the DNA-binding activity of the transcription factor AP-1. These changes were significant at a dose of 1 mg/kg of NBI30775. CONCLUSION: NBI30775 reduces levels of anxiety in mice (under basal conditions) with a steep dose-response curve. Molecules such as GR, MR, BAG-1 and AP-1 have been identified as some of the drug's intracellular targets; interestingly, changes in these molecules have also been seen in response to conventional antidepressants, showing that structurally and mechanistically unrelated anxiolytic and antidepressant drugs can influence common downstream pathways. [Abstract]
Modell
S, Yassouridis A, Huber J, Holsboer F. Corticosteroid receptor function
is decreased in depressed patients. Neuroendocrinology 1997
Mar;65(3):216-22 "Decreased feedback control of the hypothalamic-pituitary-adrenocortical
(HPA) system as revealed by the combined dexamethasone and corticotropin-releasing
hormone (DEX-CRH) test has been documented in the vast majority of patients with
affective disorders. This finding was interpreted as a failure at the level of
the glucocorticoid receptor (GR)-mediated feedback action, which apparently fails
to restrain HPA activity in the presence of elevated plasma corticosteroid levels.
To test this hypothesis we conducted the DEX/CRH test using increasing doses of
DEX in order to establish a dose-response relationship. We used three different
DEX doses (0.75, 1.5, 3.0 mg) in three groups of depressed patients and controls.
As expected, increasing DEX doses were associated with decreasing amounts of adrenocorticotropin
(ACTH) and cortisol being released after CRH injection. However, dose-response
curves for both plasma ACTH and cortisol concentrations were shifted to higher
area under the curve (AUC) values among patients compared to controls. Pretreatment
with 0.75 and 1.5 mg DEX produced significantly higher AUC values for both plasma
ACTH and cortisol values among patients. These differences became less obvious
with the higher DEX doses, indicating that the dose of 1.5 mg used in the majority
of clinical studies so far is well suited to differentiate between healthy controls
and patients. The reported data here are consistent with the hypothesis that an
altered GR capacity or function underlies the exaggerated HPA activity in depression."
[Abstract] Michael
Deuschle, Ulrich Schweiger, Bettina Weber, Ulrike Gotthardt, Andreas Körner,
Jurgen Schmider, Harald Standhardt, Claas-Hinrich Lammers, and Isabella Heuser
Diurnal Activity and Pulsatility of the Hypothalamus-Pituitary-Adrenal
System in Male Depressed Patients and Healthy Controls J.
Clin. Endocrinol. Metab. 82: 234-238 "There is only sparse and ambiguous
information about circadian and pulsatile secretion features of the hypothalamus-pituitary-adrenocortical
system in depression. We studied 15 severely depressed (Hamilton Depression Scale
30.4 +/- 6.7) male patients (age 22-72 yr; mean, 47.7 +/- 14.8) and 22 age-matched
male controls (age 23-85 yr; mean, 53.1 +/- 18.2). Twenty-four-hour blood sampling
from 0800-0800 h with 30-min sampling intervals was performed; from 1800-2400
h, blood was drawn every 10 min. Multivariate analysis of covariance, with the
covariate being age, revealed mean 24-h cortisol (315.9 +/- 58.5 vs. 188.2 +/-
27.3 nmol/L) and mean ACTH (7.82 +/- 1.94 vs. 5.79 +/- 1.28 pmol/L) to be significantly
increased in depressed patients. The frequency of cortisol (2.6 +/- 0.7 vs. 1.3
+/- 1.0 pulses/6 h) and ACTH (2.6 +/- 1.6 vs. 1.6 +/- 1.4 pulses/6 h) pulses during
the evening were higher in patients compared to controls. The flattened circadian
cortisol variation and reduced time of quiescence of cortisol secretory activity
(140 +/- 116 vs. 305 +/- 184 min) in patients suggest disturbances of circadian
functions. We conclude that increased hypothalamus-pituitary-adrenocortical activity
in depression is related to a greater frequency of episodic hormone release, and
we hypothesize that the observed circadian changes might be partly due to altered
mineralocorticoid and glucocorticoid receptor capacity and function." [Full
Text] Calfa G, Kademian S, Ceschin D, Vega G,
Rabinovich GA, Volosin M. Characterization and functional significance
of glucocorticoid receptors in patients with major depression: modulation by antidepressant
treatment. Psychoneuroendocrinology. 2003 Jul; 28(5): 687-701. "Hyperactivity
of the hypothalamic pituitary adrenal (HPA) axis in patients with major depression
is one of the most consistent findings in biological psychiatry. Experimental
data support the idea that glucocorticoid-mediated feedback via glucocorticoid
receptors (GR) is impaired in major depression. The aim of the present work was
to assess the putative changes in GR density of peripheral blood mononuclear cells
(PBMCs) in a group of patients with major depression and to determine modulation
of these GR sites by antidepressant treatment. In addition, susceptibility of
PBMCs to glucocorticoid effects was also studied using a functional end-point
analysis in vitro, such as cortisol inhibition of mitogen-induced lymphocyte proliferation.
Cortisol levels were also measured before and after dexamethasone suppression
test (DST). The results showed a decrease in GR density in depressed patients
compared with healthy subjects, mainly in those patients that showed basal cortisol
levels in the upper normal range and were refractory to DST. Regarding the functional
significance of this variation, two representative groups emerged from our study:
a) free-medication patients with GR function comparable to healthy controls, and
b) patients showing diminished GR activity. These results suggest a lack of relationship
between GR density and cortisol-induced inhibition of lymphocyte proliferation.
Patients treated with different antidepressant drugs showed a marked increase
in the number of GR sites per cell compared to non-treated. Interestingly, this
increase was even higher than in normal subjects. Hence, restoration of GR density
after an efficient antidepressant treatment could be an index of an effective
modulatory action of drugs on GR expression and highlights the possibility that
GR levels might be used as markers of a successful treatment." [Abstract] Yehuda
R, Boisoneau D, Mason JW, Giller EL. Glucocorticoid receptor number
and cortisol excretion in mood, anxiety, and psychotic disorders. Biol
Psychiatry 1993 Jul 1-15;34(1-2):18-25 "In the present study, we measured
cytosolic lymphocyte glucocorticoid receptor and 24-hour urinary cortisol excretion
in patients with major depressive disorder, bipolar mania, posttraumatic stress
disorder, panic disorder, and schizophrenia. Patients with major depression had
the smallest, and posttraumatic stress disordered patients the largest, mean number
of glucocorticoid receptors per cell compared to patients in the other groups.
Bipolar manic and panic patients did not differ from each other in regard to the
number of lymphocyte glucocorticoid receptors. Bipolar manic and panic patients
did have significantly more glucocorticoid receptors/cell than schizophrenic patients.
The mean 24-hour urinary cortisol excretion was significantly higher in patients
with major depression and bipolar mania than in those in the other diagnostic
groups. Lymphocyte glucocorticoid receptor number and cortisol excretion tended
to be inversely related, when the entire sample was considered as a whole, but
this effect did not reach statistical significance. It is concluded that lymphocyte
glucocorticoid receptors may be modulated by multiple influences, not just ambient
cortisol levels. These preliminary data suggest that the assessment of lymphocyte
glucocorticoid receptor number in tandem with cortisol levels may provide a more
meaningful estimate of hypothalamic-pituitary-adrenal axis activity than is achieved
using cortisol alone." [Abstract] Rupprecht
R, Kornhuber J, Wodarz N, Lugauer J, Gobel C, Riederer P, Beckmann H. Lymphocyte
glucocorticoid receptor binding during depression and after clinical recovery. J
Affect Disord 1991 May-Jun;22(1-2):31-5 "Lymphocyte glucocorticoid receptor
binding parameters were studied in 15 severely depressed patients during depression
and after clinical recovery, and in 15 healthy controls. There was no difference
in glucocorticoid receptor number or affinity between depressed patients and recovered
or control subjects. Afternoon ACTH and cortisol concentrations did not differ
significantly between the three groups. No relationship could be established between
glucocorticoid receptor binding and antidepressant medication. These data support
the view of an impaired ligand-induced plasticity of glucocorticoid receptor regulation
rather than the hypothesis of decreased glucocorticoid receptor numbers during
depression." [Abstract]
Whalley LJ, Borthwick N, Copolov D, Dick H, Christie
JE, Fink G. Glucocorticoid receptors and depression. Br
Med J (Clin Res Ed) 1986 Mar 29;292(6524):859-61 "The number of glucocorticoid
receptor sites in lymphocytes was estimated and plasma cortisol concentrations
measured in 17 depressed patients, 12 patients with chronic schizophrenia, and
31 healthy control subjects. The number of receptor sites was significantly lower
in the depressed patients than in either the controls or the patients with chronic
schizophrenia, but there were no differences between the groups in the dissociation
constants of the glucocorticoid receptors or the plasma cortisol concentrations.
When two control subjects were studied intensively over 28 hours a slight diurnal
variation in the number of glucocorticoid receptors was detected. The lower numbers
of glucocorticoid receptors in the lymphocytes of depressed patients may explain
why such patients, who often have hypercortisolaemia, do not show the clinical
features of excess production of cortisol." [Abstract]
Gormley GJ, Lowy MT, Reder AT, Hospelhorn VD, Antel
JP, Meltzer HY. Glucocorticoid receptors in depression: relationship
to the dexamethasone suppression test. Am J Psychiatry 1985
Nov;142(11):1278-84 "Cytoplasmic glucocorticoid receptor content wa quantitated
in lymphocytes from unmedicated depressed patients and control subjects before
and after a standardized dexamethasone suppression test. Depressed patients (N
= 11) had significantly lower (32%) basal cytoplasmic glucocorticoid receptor
content than the control group (N = 14). Suppression of serum cortisol (5.0 micrograms/dl
or less) in both control and depressed subjects (N = 16) following dexamethasone
(1 mg) was associated with a decrease in lymphocyte cytoplasmic glucocorticoid
receptor number, whereas no such change occurred in cortisol nonsuppressors (N
= 9). Changes in receptor concentration were positively correlated with postdexamethasone
serum cortisol levels and with the inhibitory effect of dexamethasone on mitogen-induced
lymphocyte proliferation." [Abstract] Wassef
A, Smith EM, Rose RM, Gardner R, Nguyen H, Meyer WJ. Mononuclear
leukocyte glucocorticoid receptor binding characteristics and down-regulation
in major depression. Psychoneuroendocrinology 1990;15(1):59-68 "Some
patients with major depressive disorder (MDD) have elevated plasma cortisol concentrations
and show failure to suppress cortisol secretion upon administration of dexamethasone
(DEX), yet they do not have Cushingoid features. To study whether this represents
glucocorticoid (GC) resistance, [3H]-DEX-binding assays were used to measure,
in vitro, the GC receptor affinity (1/Kd) and number (Bmax) in mononuclear leukocytes
of 11 MDD patients and 15 control subjects. No receptor abnormalities were detected
in the MDD group; thus any cellular defect leading to a lack of responsiveness
to GC in the MDD patients, if present, probably lies beyond the initial receptor
binding. DEX (1.0 mg orally) was administered to study in vivo GC receptor down-regulation.
Compared to the control group, fewer depressed subjects down-regulated Bmax after
DEX. By paired t-test, Bmax decreased significantly in the control group but not
in the depressed group. Receptor number on the control day did not correlate significantly
with the degree of receptor down-regulation, severity of depression or cortisol
concentrations across all the subjects. These results do not lend support to previous
reports suggesting that GC resistance in MDD results from a GC receptor-binding
abnormality, and they emphasize the importance of considering receptor studies
in the context of GC-mediated cell processes in order to identify the exact cellular
defect(s) leading to GC resistance." [Abstract]
McQUADE,
RICHARD, YOUNG, ALLAN H. Y. Future therapeutic targets in mood disorders:
the glucocorticoid receptor Br J Psychiatry 2000 177: 390-395 "BACKGROUND:
The hypercortisolaemia and dysfunction of the hypothalamic-pituitary-adrenal (HPA)
axis associated with mood disorders have been attributed to a breakdown in the
glucocorticoid-receptor-mediated negative feedback mechanism regulating HPA activity.
Reinstating normal feedback may be therapeutic in mood disorders. AIMS: To review
the evidence for the involvement of the glucocorticoid receptor in the pathogenesis
and treatment of mood disorders. METHOD: Medline and hand searches were carried
out, selecting literature relevant to psychiatrists and psychopharmacologists.
RESULTS: A dysfunction in glucocorticoid receptors is integral to the HPA abnormalities
of mood disorders. Antidepressant and mood-stabilising drugs can up-regulate glucocorticoid
receptors, restoring glucocorticoid function. Preliminary clinical studies targeting
the glucocorticoid receptor are encouraging. CONCLUSIONS: Drugs designed specifically
to up-regulate glucocorticoid receptors may be integral to future strategies in
treating mood disorders." [Full
Text]
Wolkowitz, Owen M., Reus, Victor I. Treatment of
Depression With Antiglucocorticoid Drugs Psychosom Med 1999
61: 698-711 "OBJECTIVE: The theoretical and empirical rationales for the
potential therapeutic use of antiglucocorticoid agents in the treatment of depression
are reviewed. METHOD: Individual case reports, case series, open-label, and double-blind,
controlled trials of the usage of cortisol-lowering treatments in Cushing's syndrome
and major depression are evaluated and critiqued. RESULTS: In each of the 28 reports
of antiglucocorticoid treatment of Cushing's syndrome, antidepressant effects
were noted in some patients; the largest two series document a response rate of
70% to 73%. Full response, however, was at times erratic and delayed. Across the
11 studies of antiglucocorticoid treatment of major depression, some degree of
antidepressant response was noted in 67% to 77% of patients. Antidepressant or
antiobsessional effects of antiglucocorticoid augmentation of other psychotropic
medications have also been noted in small studies of patients with treatment-resistant
depression, obsessive-compulsive disorder, and schizoaffective disorder or schizophrenia.
CONCLUSIONS: These promising results with antiglucocorticoid treatment must be
interpreted cautiously because of the small sample sizes and heterogeneity of
the studies reviewed, the bias favoring publication of positive results, and the
open-label nature of most of the studies. Although definitive controlled trials
remain to be conducted, there is a consistent body of evidence indicating that
cortisol-lowering treatments may be of clinical benefit in select individuals
with major depression and other hypercortisolemic conditions." [Full
Text] Lowy MT, Reder AT, Gormley GJ, Meltzer HY. Comparison
of in vivo and in vitro glucocorticoid sensitivity in depression: relationship
to the dexamethasone suppression test. Biol Psychiatry 1988
Oct;24(6):619-30 "The effect of in vivo (1 mg) and in vitro (10(-7)-10(-10)
M) dexamethasone administration on mitogen-induced lymphocyte proliferation was
examined in drug-free depressed patients, nondepressed psychiatric patients, as
well as normal controls, and was related to the results of a standard overnight
Dexamethasone Suppression Test (DST). The effect of oral dexamethasone administration
was also examined for its effect on lymphocyte cytosolic glucocorticoid receptor
content. Oral dexamethasone administration significantly decreased both phytohemagglutinin
(PHA) and concanavalin A (Con-A) induced lymphocyte proliferation, as well as
glucocorticoid receptor number in suppressors, whereas dexamethasone failed to
decrease these responses in nonsuppressors. Nonsuppressors had significantly lower
serum dexamethasone levels compared to suppressors at both 8:00 AM and 4:00 PM.
However, when differences in serum dexamethasone levels were covaried out, there
were still significant differences between suppressors and nonsuppressors on the
dexamethasone-induced mitogen changes, but the changes in glucocorticoid receptor
content were no longer significant. In vitro incubation of lymphocytes with dexamethasone
produced a dose-related decrease in mitogenesis, which was not different between
the depressed and nondepressed groups. However, at physiologically relevant concentrations
of dexamethasone (10(-9)-10(-10) M), nonsuppressors as compared to suppressors
were more resistant to the immunosuppressive effects of in vitro dexamethasone
on the Con-A response. The inhibitory effect of in vitro dexamethasone on Con-A-stimulated
lymphocytes was positively correlated with basal 4:00 PM cortisol values. In conclusion,
in vitro techniques are useful probes to assess glucocorticoid sensitivity in
depression. The present results also further support the hypothesis that glucocorticoid
insensitivity is associated with DST nonsuppression." [Abstract] Cole
MA, Kim PJ, Kalman BA, Spencer RL. Dexamethasone suppression of corticosteroid
secretion: evaluation of the site of action by receptor measures and functional
studies. Psychoneuroendocrinology 2000 Feb;25(2):151-67 "A
dose of dexamethasone was determined in rats (50 micrograms/kg s.c.) that suppressed
the corticosterone response to restraint stress by 80%. Corticosteroid receptor
occupancy estimates found that the 50 micrograms/kg s.c. dose of dexamethasone
had no significant effect on available glucocorticoid receptor (GR) or mineralocorticoid
receptor (MR) binding in brain regions (hypothalamus, hippocampus and cortex);
on the other hand dexamethasone produced a selective and significant decrease
in available GR in peripheral tissues (pituitary and spleen). Functional studies
showed that the 50 micrograms/kg s.c. dose of dexamethasone completely blocked
the effects of corticotropin-releasing hormone (CRH; 0.3-3.0 micrograms/kg i.p.)
on corticosterone secretion, but did not inhibit the corticosterone response to
an adrenocorticotropin hormone (ACTH; 2.5 I.U./kg i.p.) challenge. These studies
indicate that this dose of dexamethasone exerts its inhibitory effects on the
HPA axis primarily by acting at GR in the pituitary. The plasma dexamethasone
levels produced by this dose of dexamethasone are similar to those present in
humans the afternoon after an oral dexamethasone suppression test (DST), a time
at which many depressed patients escape from dexamethasone suppression. These
results support and extend other studies which suggest that the DST provides a
direct test of the effects of increased GR activation in the pituitary on ACTH
and cortisol secretion." [Abstract] Meyer
U, van Kampen M, Isovich E, Flugge G, Fuchs E. Chronic psychosocial
stress regulates the expression of both GR and MR mRNA in the hippocampal formation
of tree shrews. Hippocampus 2001;11(3):329-36 "A
persistent hyperactivity of the hypothalamic-pituitary-adrenal axis and thus elevated
glucocorticoid levels are main neuroendocrine features of depressive symptomatology
in humans. The broad range of effects that are set off by glucocorticoids is mediated
by glucocorticoid receptors (GRs) and mineralocorticoid receptors (MRs), which
themselves are subject to autoregulation. In order to investigate the impact of
long-lasting psychological stress on corticosteroid receptor mRNA expression in
the hippocampal formation, we employed the psychosocial stress paradigm in male
tree shrews (Tupaia belangeri). By in situ hybridization studies and semiquantitative
evaluation of stress-induced changes of GR and MR mRNA expression at the single-cell
level, brain tissue from subordinate animals which were exposed to 27 days (1
h/day) of social confrontation was compared to that of nonstressed animals. Four
weeks of stress exposure resulted in a downregulation of GR mRNA in the dentate
gyrus and hippocampal subfields CA1 and CA3 of subordinate male tree shrews compared
to controls. The MR mRNA content in these subfields of the anterior hippocampus
was also clearly reduced. On the contrary, in a more posterior location on the
longitudinal axis of the tree shrew hippocampus, the MR message was increased
in subfields CA1 and CA3 and in the dentate gyrus. These results suggest a relevance
of the stress-induced regulation of both corticosteroid receptor subtype mRNAs
in a naturalistic challenging situation. Moreover, the differential regulation
of MR mRNA along the rostrocaudal axis of the hippocampus adds another feature
to the heterogenous composition of this structure." [Abstract] Mizoguchi
K, Ishige A, Aburada M, Tabira T. Chronic stress attenuates glucocorticoid
negative feedback: involvement of the prefrontal cortex and hippocampus. Neuroscience.
2003; 119(3): 887-97. "Disruption of the glucocorticoid negative feedback
system is observed in approximate one half of human depressives, and a similar
condition is induced in animals by chronic stress. This disruption is thought
to involve down-regulation of glucocorticoid receptors (GRs) in the feedback sites
of the brain. However, the responsible site of the brain has not been well elucidated.
Here we examined the effects of chronic stress induced by water immersion and
restraint (2 h/day) for 4 weeks followed by recovery for 10 days on the GR levels
in the prefrontal cortex (PFC), hippocampus, and hypothalamus of rats using a
Western immunoblot technique. In the PFC, the cytosolic GR levels were decreased,
but the nuclear GR levels were not changed. In the hippocampus, the levels of
cytosolic and nuclear GRs were increased. However, there were no marked changes
in the GR levels in the hypothalamus. The changes in the cytosolic GR levels were
confirmed at the mRNA level by an in situ hybridization technique. We next examined
the suppressive effects of dexamethasone (DEX) infusions into these regions on
the circulating corticosterone levels. When DEX was infused into the PFC or hippocampus
of the chronically stressed rats, the suppressive response to DEX was abolished,
but the response was normal in the hypothalamus. In addition, when DEX was injected
systemically to the chronically stressed rats, the suppressive response to DEX
was significantly attenuated. These results suggest that the abnormal changes
in GRs in the higher centers of the hypothalamo-pituitary-adrenal axis are involved
in the chronic stress-induced attenuation of the feedback. Since dysfunction of
the PFC or hippocampus is implicated in the pathogenesis of depression, the present
findings would help to understand the mechanisms underlying the disrupted feedback
system and its relation to brain dysfunction in depression." [Abstract] Xing
GQ, Russell S, Webster MJ, Post RM. Decreased expression of mineralocorticoid
receptor mRNA in the prefrontal cortex in schizophrenia and bipolar disorder. Int
J Neuropsychopharmacol. 2004 Mar;:1-11. [Epub ahead of print] "Abnormal
prefrontal cortical activity, activation of the hypothalamicpituitaryadrenal (HPA)
axis, and deficits in slow-wave sleep (SWS) have been extensively reported in
patients with affective disorders and schizophrenia, yet the underlying pathophysiological
mechanisms have not been completely elucidated. Mineralocorticoid receptor (MR)
and glucocorticoid receptor (GR) are two nuclear hormone receptors of primary
importance in the control of stress-related and circadian HPA activity. A recent
study showed that blocking brain MR activity not only enhances CRF-induced ACTH
and cortisol release, but also significantly reduces SWS in humans. We hypothesized
that the expression of MR would be deficient in the prefrontal cortex of patients
with schizophrenia and affective disorders. The MR mRNA expression in the post-mortem
prefrontal cortex of patients with major depression (MD), bipolar (BP), and schizophrenic
(SZ) disorders and non-psychiatric controls (n=15 for each patient group, and
n=14 for controls) was determined by in-situ hybridization. In the dorsolateral
prefrontal cortex Brodmanns area 9 (BA 9), MR mRNA was significantly lower (p0.05)
in all laminae (IVI) in BP, and in laminae I, III, IV and VI in SZ than in the
controls. MR mRNA in BA 9 was negatively correlated with the duration of psychiatric
illnesses. In BA 46, MR mRNA was not significantly different among groups, but
was positively correlated with brain pH. These results provide the first evidence
of deficient prefrontal MR mRNA expression in BP and SZ. Whether these findings
may be linked to the abnormal prefrontal function, HPA axis activation, or the
deficits in SWS found in these major psychiatric illnesses remains to be further
explored." [Abstract] Blom
JM, Tascedda F, Carra S, Ferraguti C, Barden N, Brunello N. Altered
regulation of CREB by chronic antidepressant administration in the brain of transgenic
mice with impaired glucocorticoid receptor function. Neuropsychopharmacology
2002 May;26(5):605-14 "Various effects of antidepressant drugs on gene
transcription have been described and altered gene expression has been proposed
as being a common biological basis underlying depressive illness. One target for
the common action of antidepressants is a modifying effect on the regulation of
postreceptor pathways and genes related to the cAMP cascade. Recent studies have
demonstrated that long-term antidepressant treatment resulted in sustained activation
of the cyclic adenosine 3',5'-monophosphate system and in increased expression
of the transcription factor cAMP response element binding protein (CREB). A transgenic
animal model of depression with impaired glucocorticoid receptor function was
used to investigate the effect of chronic antidepressant treatments on CREB expression
in different brain areas. Wild-type and transgenic mice received one administration
of saline, desipramine, or fluoxetine, daily for 21 days. The effects of antidepressants
on CREB mRNA were analyzed using a sensitive RNase protection assay. Antidepressant
treatment resulted in a neuroanatomically and animal specific expression pattern
of CREB. Our findings suggest that life-long central glucocorticoid receptor dysfunction
results in an altered sensitivity with respect to the effects of antidepressants
on the expression of CREB." [Abstract]
Paskitti
ME, McCreary BJ, Herman JP. Stress regulation of adrenocorticosteroid
receptor gene transcription and mRNA expression in rat hippocampus: time-course
analysis. Brain Res Mol Brain Res 2000 Sep 15;80(2):142-52 "Neuronal
glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) proteins mediate
the transcriptional effects of circulating glucocorticoids. These receptors bind
the same DNA response element, yet mediate quite different cellular functions.
The present study tests the hypothesis that acute and chronic stress, which cause
increases in glucocorticoids sufficient to bind the GR, will regulate expression
of the GR and MR genes in the hippocampal formation. Analysis of MR gene transcription
using an intronic MR probe revealed a transient 50% decrease in MR hnRNA in CA1,
CA3 and dentate gyrus at 60-120 min post-stress, consistent with glucocorticoid
down-regulation of the MR gene. However, no changes were seen in full-length MR
mRNA at any post-stress time point. In contrast, GR hnRNA was not affected by
acute stress, but GR mRNA was decreased 120 min post stress in all hippocampal
subregions. Chronic stress exposure down-regulated GR mRNA in CA3 only; effects
were first evident 7 days post stress and persisted for the entire stress time-course
(28 days). There was no evidence for down-regulation of GR hnRNA or MR hnRNA/mRNA
at any point in the chronic stress regimen. The transient decrease in MR hnRNA
in the absence of mRNA changes suggests increased MR mRNA stability. In contrast,
acute stress decreases the availability of GR mRNA without demonstrably affecting
transcription, suggesting reduced GR mRNA stability. The results suggest that
acute stress alters GR mRNA expression by largely post-transcriptional mechanisms.
However, elevations in basal corticosterone secretion seen following chronic stress
are not sufficient to markedly down-regulate GR/MR expression in a long-term fashion."
[Abstract] Sheng
Z, Yanai A, Fujinaga R, Kawano J, Tanaka M, Watanabe Y, Shinoda K. Gonadal
and adrenal effects on the glucocorticoid receptor in the rat hippocampus, with
special reference to regulation by estrogen from an immunohistochemical view-point. Neurosci
Res. 2003 Jun; 46(2): 205-18. "Focusing on the hippocampal CA1 region,
effects of peripheral gonadal and adrenal steroids on the glucocorticoid receptor
(GR) were immunohistochemically evaluated in male and female adult rat brains
after adrenalectomy (ADX), gonadectomy (GDX), and administration of estradiol
(E2) and/or corticosterone (CS). In ADXed male rats, the hippocampal nuclear GR
decreased and turned back to the cytoplasm, whereas in females, nuclear localization
persisted even after ADX. In GDX+ADXed female rats, the GR was dispersedly translocated
from the nucleus to the cytoplasm as well as in GDX+ADXed males. The dispersed
cytoplasmic GR was again translocated into the nucleus by administration of CS.
In addition, administration of a small dose of E2 for 4-13 days was found to sufficiently
recover the nuclear location of GR in GDX+ADXed rat brains, whereas medium-to-large
doses could not do this. Also, a longer administration more strongly enhances
the nuclear GR location and expression. The present study provided strong immunohistochemical
evidence that the sexually dimorphic effects of ADX on hippocampal GR are attributable
to gonadal hormones, and that E2 is implicated in the effects in inversely-dose-
and directly-duration-dependent manner. Taken together, intriguing gonadal and
adrenal crosstalk is considered to play some important role in regulating hippocampal
GR morphology and to have a possibly crucial influence on stress-related disorders
such as depression." [Abstract] Miller
AH, Pariante CM, Pearce BD. Effects of cytokines on glucocorticoid
receptor expression and function. Glucocorticoid resistance and relevance to depression. Adv
Exp Med Biol 1999;461:107-16 "Our data indicate that the proinflammatory
cytokine, IL-1alpha inhibits GR translocation and hormone-induced GR-mediated
gene transcription, and, in conjunction with previous in vivo and in vitro studies,
can be interpreted to suggest that cytokines have the capacity to contribute to
glucocorticoid resistance and thus the pathophysiology of depression. In addition,
data from our mouse viral studies in glucocorticoid deficient animals demonstrate
that endogenous glucocorticoids modulate a delicate balance between viral defense
and cytokine toxicity. Finally, the antidepressant, DMI, has been found to enhance
GR translocation and GR-mediated gene transcription and thus may provide a useful
strategy for adjusting neuroendocrine setpoints in vivo. Taken together, these
findings suggest that factors which modulate glucocorticoid action (e.g. cytokines
and antidepressants) will be relevant contributors to disease expression including
behavioral toxicity and sickness behavior." [Abstract] Carmine
M. Pariante, Bradley D. Pearce, Tracy L. Pisell, Carmen I. Sanchez, Cecilia Po,
Cindy Su, and Andrew H. Miller The Proinflammatory Cytokine, Interleukin-1,
Reduces Glucocorticoid Receptor Translocation and Function Endocrinology
140: 4359-4366 [Full
Text] Young EA, Lopez JF, Murphy-Weinberg V, Watson
SJ, Akil H. Mineralocorticoid receptor function in major depression. Arch
Gen Psychiatry. 2003 Jan; 60(1): 24-8. "BACKGROUND: Negative feedback
regulation of the hypothalamic-pituitary-adrenal axis occurs through a dual-receptor
system of mineralocorticoid receptors (MR) and glucocorticoid receptors (GR).
Their affinity for cortisol and their distribution in the brain differ. Studies
using an MR antagonist have demonstrated that MR is active throughout the circadian
rhythm. Because major depression is accompanied by increased glucocorticoid secretion
and insensitivity to glucocorticoid feedback, and because glucocorticoids are
capable of down-regulating MR and GR, we expected that major depression would
be accompanied by decreased MR activity. METHODS: To test this hypothesis, we
administered spironolactone, an MR antagonist, to individuals with major depression
and matched control subjects and assessed levels of corticotropin and cortisol
secretion in response to this acute challenge. Studies were conducted in the morning,
the time of peak activation of the hypothalamic-pituitary-adrenal axis. All patients
were currently depressed and free of all medications. All controls were free of
all psychiatric diagnoses and of all medications. RESULTS: Spironolactone treatment
resulted in a significant increase in cortisol secretion levels in both groups.
Depressed patients demonstrated higher cortisol secretion levels than control
subjects. In addition, depressed patients demonstrated a different pattern of
increase in cortisol secretion levels after spironolactone administration. Furthermore,
a significant effect of spironolactone treatment on corticotropin secretion levels
can be observed in depressed patients, whereas controls show no such effect. CONCLUSIONS:
Despite high baseline cortisol levels, patients with major depression show high
functional activity of the MR system. Paired with the body of evidence regarding
decreased sensitivity to GR agonists, these data suggest an imbalance in the MR/GR
ratio. The balance of MR and GR is known to affect brain serotonin systems and
may play an etiologic role in serotonin receptor changes observed in patients
with major depression." [Abstract] Bremner
JD, Vythilingam M, Vermetten E, Anderson G, Newcomer JW, Charney DS. Effects
of glucocorticoids on declarative memory function in major depression. Biol
Psychiatry. 2004 Apr 15;55(8):811-5. "BACKGROUND: Major depression has
been associated with hypercortisolemia in a subset of patients with depression.
Administration of exogenous cortisol and other glucocorticoids to healthy human
subjects has been observed to result in a transient impairment in verbal declarative
memory function. The purpose of this study was to assess the effects of the glucocorticoid,
dexamethasone, on verbal declarative memory function in patients with untreated
unipolar major depressive disorder (MDD). METHODS: Fifty two men and women with
(n = 28) and without (n = 24) MDD received placebo or dexamethasone (1 mg and
2 mg on 2 successive days) in a double-blind, randomized fashion. Declarative
memory was assessed with paragraph recall at baseline (day 1) and day 3. RESULTS:
There was a significant interaction between diagnosis and drug (dexamethasone
vs. placebo) on paragraph recall. In the healthy subjects, memory improved from
baseline to day 3 with placebo and was unchanged with dexamethasone, whereas in
MDD patients memory function showed a pattern of decreasing with placebo and improving
with dexamethasone from baseline to day 3. CONCLUSIONS: These findings are consistent
with an altered sensitivity of declarative memory function in MDD to regulation
by glucocorticoids. Possible explanations of the findings include alterations
in glucocorticoid receptors in the hippocampus or other brain regions mediating
declarative memory, or differential sensitivity to dexamethasone-induced reductions
in cortisol, in patients with MDD." [Abstract]
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