Glucocorticoid receptors signaling impairment potentiates amyloid-ß oligomers-induced pathology in an acute model of Alzheimer's disease.

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis occurs early in Alzheimer's disease (AD), associated with elevated circulating glucocorticoids (GC) and glucocorticoid receptors (GR) signaling impairment. However, the precise role of GR in the pathophysiology of AD remains unclear. Using an acute model of AD induced by the intracerebroventricular injection of amyloid-ß oligomers (oAß), we analyzed cellular and behavioral hallmarks of AD, GR signaling pathways, processing of amyloid precursor protein, and enzymes involved in Tau phosphorylation. We focused on the prefrontal cortex (PFC), particularly rich in GR, early altered in AD and involved in HPA axis control and cognitive functions. We found that oAß impaired cognitive and emotional behaviors, increased plasma GC levels, synaptic deficits, apoptosis and neuroinflammatory processes. Moreover, oAß potentiated the amyloidogenic pathway and enzymes involved both in Tau hyperphosphorylation and GR activation. Treatment with a selective GR modulator (sGRm) normalized plasma GC levels and all behavioral and biochemical parameters analyzed. GR seems to occupy a central position in the pathophysiology of AD. Deregulation of the HPA axis and a feed-forward effect on PFC GR sensitivity could participate in the etiology of AD, in perturbing Aß and Tau homeostasis. These results also reinforce the therapeutic potential of sGRm in AD.

Resetting the Stress System with a Mifepristone Challenge.

Psychotic depression is characterized by elevated circulating cortisol, and high daily doses of the glucocorticoid/progesterone antagonist mifepristone for 1 week are required for significant improvement. Using a rodent model, we find that such high doses of mifepristone are needed because the antagonist is rapidly degraded and poorly penetrates the blood-brain barrier, but seems to facilitate the entry of cortisol. We also report that in male C57BL/6J mice, after a 7-day treatment with a high dose of mifepristone, basal blood corticosterone levels were similar to that of vehicle controls. This is surprising because after the first mifepristone challenge, corticosterone remained elevated for about 16 h, and then decreased towards vehicle control levels at 24 h. At that time, stress-induced corticosterone levels of the 1xMIF were sevenfold higher than the 7xMIF group, the latter response being twofold lower than controls. The 1xMIF mice showed behavioral hyperactivity during exploration of the circular hole board, while the 7xMIF mice rather engaged in serial search patterns. To explain this rapid reset of corticosterone secretion upon recurrent mifepristone administration, we suggest the following: (i) A rebound glucocorticoid feedback after cessation of mifepristone treatment. (ii) Glucocorticoid agonism in transrepression and recruitment of cell-specific coregulator cocktails. (iii) A more prominent role of brain MR function in control of stress circuit activity. An overview table of neuroendocrine MIF effects is provided. The data are of interest for understanding the mechanistic underpinning of stress system reset as treatment strategy for stress-related diseases.

Glucocorticoid antagonism limits adiposity rebound and glucose intolerance in young male rats following the cessation of daily exercise and caloric restriction.

Severe caloric restriction (CR), in a setting of regular physical exercise, may be a stress that sets the stage for adiposity rebound and insulin resistance when the food restriction and exercise stop. In this study, we examined the effect of mifepristone, a glucocorticoid (GC) receptor antagonist, on limiting adipose tissue mass gain and preserving whole body insulin sensitivity following the cessation of daily running and CR. We calorically restricted male Sprague-Dawley rats and provided access to voluntary running wheels for 3 wk followed by locking of the wheels and reintroduction to ad libitum feeding with or without mifepristone (80 mg·kg(-1)·day(-1)) for 1 wk. Cessation of daily running and CR increased HOMA-IR and visceral adipose mass as well as glucose and insulin area under the curve during an oral glucose tolerance test vs. pre-wheel lock exercised rats and sedentary rats (all P < 0.05). Insulin sensitivity and glucose tolerance were preserved and adipose tissue mass gain was attenuated by daily mifepristone treatment during the post-wheel lock period. These findings suggest that following regular exercise and CR there are GC-induced mechanisms that promote adipose tissue mass gain and impaired metabolic control in healthy organisms and that this phenomenon can be inhibited by the GC receptor antagonist mifepristone.

Differential targeting of brain stress circuits with a selective glucocorticoid receptor modulator.

Glucocorticoid receptor (GR) antagonism may be of considerable therapeutic value in stress-related psychopathology such as depression. However, blockade of all GR-dependent processes in the brain will lead to unnecessary and even counteractive effects, such as elevated endogenous cortisol levels. Selective GR modulators are ligands that can act both as agonist and as antagonist and may be used to separate beneficial from harmful treatment effects. We have discovered that the high-affinity GR ligand C108297 is a selective modulator in the rat brain. We first demonstrate that C108297 induces a unique interaction profile between GR and its downstream effector molecules, the nuclear receptor coregulators, compared with the full agonist dexamethasone and the antagonist RU486 (mifepristone). C108297 displays partial agonistic activity for the suppression of hypothalamic corticotropin-releasing hormone (CRH) gene expression and potently enhances GR-dependent memory consolidation of training on an inhibitory avoidance task. In contrast, it lacks agonistic effects on the expression of CRH in the central amygdala and antagonizes GR-mediated reduction in hippocampal neurogenesis after chronic corticosterone exposure. Importantly, the compound does not lead to disinhibition of the hypothalamus-pituitary-adrenal axis. Thus, C108297 represents a class of ligands that has the potential to more selectively abrogate pathogenic GR-dependent processes in the brain, while retaining beneficial aspects of GR signaling.

1H-Pyrazolo[3,4-g]hexahydro-isoquinolines as potent GR antagonists with reduced hERG inhibition and an improved pharmacokinetic profile.

We report the further optimization of our series 1H-pyrazolo[3,4-g]hexahydro-isoquinoline sulfonamides as GR antagonists. By incorporating a heteroaryl ketone group at the ring junction, we have obtained compounds with excellent functional GR antagonism. Optimization of the sulfonamide substituent has provided compounds with a very desirable overall profile, including minimal hERG activity, good bioavailability and in vivo efficacy.

Biochemical and Radiological Changes in Liver Steatosis Following Mifepristone Treatment in Patients With Hypercortisolism.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is the most common liver disorder in Western industrialized countries and may progress to liver injury. Cortisol is thought to play a role in the pathogenesis of NAFLD, and cortisol modulation has shown efficacy in preclinical models. However, published reports on the clinical effects of glucocorticoid receptor antagonism in these patients are limited. CASE REPORT: Two women (aged 66 and 60 years) with endogenous hypercortisolism presented with a history of hepatic steatosis, hypertension, type 2 diabetes mellitus, and dyslipidemia. Both patients declined adrenalectomy or pituitary tumor surgery, and treatment with mifepristone 300 mg daily was initiated. During mifepristone treatment (follow up durations ranging from 10 months to 5 years), improvements in hypercortisolism-related cardiometabolic abnormalities were observed, including the normalization of lipid levels and improvement of hyperglycemia. In both cases, findings on follow-up imaging revealed resolution of fatty liver, which was supported by a decrease in liver enzymes on liver function tests. No adverse events were reported. DISCUSSION: NAFLD is frequently observed in patients with endogenous hypercortisolism. Improvement in liver function tests has previously been demonstrated in patients with hypercortisolism treated with mifepristone. The present cases showed, for the first time, radiological improvement of liver steatosis following mifepristone use in patients with hypercortisolism and NAFLD. CONCLUSION: This case series demonstrated improvements in biochemical and imaging parameters of NAFLD in patients with hypercortisolism treated with mifepristone. Further research is needed to investigate the effects of glucocorticoid receptor modulation in fatty liver disease.

Efficacy and safety of mifepristone for the treatment of psychotic depression.

Open-label studies and randomized clinical trials have suggested that mifepristone may be effective for the treatment of major depression with psychotic features (psychotic depression). A recent study reported a correlation between mifepristone plasma concentration and clinical response. The current study aimed to evaluate the safety and efficacy of mifepristone and, secondarily, to test whether response was significantly greater among patients with mifepristone plasma concentrations above an a priori hypothesized threshold. A total of 433 patients who met criteria for psychotic depression were randomly assigned to receive 7 days of either mifepristone (300, 600, or 1200 mg) or placebo. Response was defined as a 50% reduction in psychotic symptoms on both days 7 and 56. Cochran-Mantel-Haenszel tests compared (1) the proportion of responders among patients assigned mifepristone versus placebo and (2) the proportion of responders among the subset of patients with plasma concentrations greater than 1660 ng/mL versus placebo. Mifepristone was well tolerated at all 3 doses. The proportion of responders randomized to mifepristone did not statistically differ from placebo. Patients with trough mifepristone plasma concentrations greater than 1660 ng/mL were significantly more likely to have a rapid and sustained reduction in psychotic symptoms than those who received placebo. The study failed to demonstrate efficacy on its primary end point. However, the replication of a statistically significant linear association between mifepristone plasma concentration and clinical response indicates that mifepristone at sufficient plasma levels may potentially be effective in rapidly and durably reducing the psychotic symptoms of patients with psychotic depression.

Selective Glucocorticoid Receptor Modulation Prevents and Reverses Nonalcoholic Fatty Liver Disease in Male Mice.

Medication for nonalcoholic fatty liver disease (NAFLD) is an unmet need. Glucocorticoid (GC) stress hormones drive fat metabolism in the liver, but both full blockade and full stimulation of GC signaling aggravate NAFLD pathology. We investigated the efficacy of selective glucocorticoid receptor (GR) modulator CORT118335, which recapitulates only a subset of GC actions, in reducing liver lipid accumulation in mice. Male C57BL/6J mice received a low-fat diet or high-fat diet mixed with vehicle or CORT118335. Livers were analyzed histologically and for genome-wide mRNA expression. Functionally, hepatic long-chain fatty acid (LCFA) composition was determined by gas chromatography. We determined very-low-density lipoprotein (VLDL) production by treatment with a lipoprotein lipase inhibitor after which blood was collected to isolate radiolabeled VLDL particles and apoB proteins. CORT118335 strongly prevented and reversed hepatic lipid accumulation. Liver transcriptome analysis showed increased expression of GR target genes involved in VLDL production. Accordingly, CORT118335 led to increased lipidation of VLDL particles, mimicking physiological GC action. Independent pathway analysis revealed that CORT118335 lacked induction of GC-responsive genes involved in cholesterol synthesis and LCFA uptake, which was indeed reflected in unaltered hepatic LCFA uptake in vivo. Our data thus reveal that the robust hepatic lipid-lowering effect of CORT118335 is due to a unique combination of GR-dependent stimulation of lipid (VLDL) efflux from the liver, with a lack of stimulation of GR-dependent hepatic fatty acid uptake. Our findings firmly demonstrate the potential use of CORT118335 in the treatment of NAFLD and underscore the potential of selective GR modulation in metabolic disease.

The role of glucocorticoid receptors in metabolic syndrome and psychiatric illness.

Glucocorticoids (GCs) are involved in a large number of the physiological changes associated with metabolic syndrome and certain psychiatric illness. Although significance is often given to the concentration of GC, its biological action is determined by the activation of intracellular GC receptors (GR). Genetic polymorphisms of the GR and the large array of GR related cofactors can directly or indirectly affect the pathophysiology and evolution of these conditions. This review will discuss the effects of GR mutations on metabolic syndrome and psychotic depression.

Identification of the Clinical Candidate (R)-(1-(4-Fluorophenyl)-6-((1-methyl-1H-pyrazol-4-yl)sulfonyl)-4,4a,5,6,7,8-hexahydro-1H-pyrazolo[3,4-g]isoquinolin-4a-yl)(4-(trifluoromethyl)pyridin-2-yl)methanone (CORT125134): A Selective Glucocorticoid Receptor (GR) Antagonist.

The nonselective glucocorticoid receptor (GR) antagonist mifepristone has been approved in the U.S. for the treatment of selected patients with Cushing's syndrome. While this drug is highly effective, lack of selectivity for GR leads to unwanted side effects in some patients. Optimization of the previously described fused azadecalin series of selective GR antagonists led to the identification of CORT125134, which is currently being evaluated in a phase 2 clinical study in patients with Cushing's syndrome.

The efficacy of mifepristone in the reduction and prevention of olanzapine-induced weight gain in rats.

Atypical antipsychotics, such as olanzapine, have been associated with clinically significant weight gain. Changes to the hypothalamic pituitary adrenal axis may partially mediate this weight increase. Two experiments were conducted to test the effects of mifepristone on both mitigating and preventing olanzapine-induced weight gain. In the first experiment, adult female Sprague-Dawley rats gained significantly more weight on average when administered olanzapine for 35 days compared to vehicle controls. Subsequently, the olanzapine-treated rats were randomized to three dose levels of mifepristone (20, 60, and 200 mg/kg) in conjunction with olanzapine. Weight measurements were taken for 21 additional days. Rats receiving olanzapine plus mifepristone rapidly lost a significant portion of the weight gained during the olanzapine only phase (p = 0.0001). Rats in the 200 mg/kg dose group had significantly less abdominal fat compared to controls (p < 0.001) at study end. In the second experiment, daily mifepristone (20, 60, 200 mg/kg) initiated concomitantly with olanzapine was compared with olanzapine alone to determine if mifepristone prevented olanzapine-induced weight gain. After 21 days of treatment, mifepristone treated rats gained significantly less weight and had significantly less abdominal fat than rats administered olanzapine alone (p = 0.0002). Results suggest that mifepristone, a potent glucocorticoid antagonist, may both reduce and prevent olanzapine-induced weight gain in rats.

New selective glucocorticoid receptor modulators reverse amyloid-ß peptide-induced hippocampus toxicity.

In Alzheimer's disease (AD), cognitive deficits and psychological symptoms are associated with an early deregulation of the hypothalamic-pituitary-adrenal axis. Here, in an acute model of AD, we investigated if antiglucocorticoid strategies with selective glucocorticoid receptor (GR) modulators (CORT108297 and CORT113176) that combine antagonistic and agonistic GR properties could offer an interesting therapeutic approach in the future. We confirm the expected properties of the nonselective GR antagonist (mifepristone) because in addition to restoring basal circulating glucocorticoids levels, mifepristone totally reverses synaptic deficits and hippocampal apoptosis processes. However, mifepristone only partially reverses cognitive deficit, effects of the hippocampal amyloidogenic pathway, and neuroinflammatory processes, suggesting limits in its efficacy. By contrast, selective GR modulators CORT108297 and CORT113176 at a dose of 20 and 10 mg/kg, respectively, reverse hippocampal amyloid-ß peptide generation, neuroinflammation, and apoptotic processes, restore the hippocampal levels of synaptic markers, re-establish basal plasma levels of glucocorticoids, and improve cognitive function. In conclusion, selective GR modulators are particularly attractive and may pave the way to new strategies for AD treatment.

Identification of a selective glucocorticoid receptor modulator that prevents both diet-induced obesity and inflammation.

BACKGROUND AND PURPOSE: High-fat diet consumption results in obesity and chronic low-grade inflammation in adipose tissue. Whereas glucocorticoid receptor (GR) antagonism reduces diet-induced obesity, GR agonism reduces inflammation, the combination of which would be desired in a strategy to combat the metabolic syndrome. The purpose of this study was to assess the beneficial effects of the selective GR modulator C108297 on both diet-induced weight gain and inflammation in mice and to elucidate underlying mechanisms. EXPERIMENTAL APPROACH: Ten-week-old C57Bl/6 J mice were fed a high-fat diet for 4 weeks while being treated with the selective GR modulator C108297, a full GR antagonist (RU486/mifepristone) or vehicle. KEY RESULTS: C108297 and, to a lesser extent, mifepristone reduced body weight gain and fat mass. C108297 decreased food and fructose intake and increased lipolysis in white adipose tissue (WAT) and free fatty acid levels in plasma, resulting in decreased fat cell size and increased fatty acid oxidation. Furthermore, C108297 reduced macrophage infiltration and pro-inflammatory cytokine expression in WAT, as well as in vitro LPS-stimulated TNF-α secretion in macrophage RAW 264.7 cells. However, mifepristone also increased energy expenditure, as measured by fully automatic metabolic cages, and enhanced expression of thermogenic markers in energy-combusting brown adipose tissue (BAT) but did not affect inflammation. CONCLUSIONS AND IMPLICATIONS: C108297 attenuates obesity by reducing caloric intake and increasing lipolysis and fat oxidation, and in addition attenuates inflammation. These data suggest that selective GR modulation may be a viable strategy for the reduction of diet-induced obesity and inflammation.

A Mixed Glucocorticoid/Mineralocorticoid Selective Modulator With Dominant Antagonism in the Male Rat Brain.

Adrenal glucocorticoid hormones are potent modulators of brain function in the context of acute and chronic stress. Both mineralocorticoid (MRs) and glucocorticoid receptors (GRs) can mediate these effects. We studied the brain effects of a novel ligand, C118335, with high affinity for GRs and modest affinity for MRs. In vitro profiling of receptor-coregulator interactions suggested that the compound is a "selective modulator" type compound for GRs that can have both agonistic and antagonistic effects. Its molecular profile for MRs was highly similar to those of the full antagonists spironolactone and eplerenone. C118335 showed predominantly antagonistic effects on hippocampal mRNA regulation of known glucocorticoid target genes. Likewise, systemic administration of C118335 blocked the GR-mediated posttraining corticosterone-induced enhancement of memory consolidation in an inhibitory avoidance task. Posttraining administration of C118335, however, gave a strong and dose-dependent impairment of memory consolidation that, surprisingly, reflected involvement of MRs and not GRs. Finally, C118335 treatment acutely suppressed the hypothalamus-pituitary-adrenal axis as measured by plasma corticosterone levels. Mixed GR/MR ligands, such as C118335, can be used to unravel the mechanisms of glucocorticoid signaling. The compound is also a prototype of mixed GR/MR ligands that might alleviate the harmful effects of chronic overexposure to endogenous glucocorticoids.

Glucocorticoid receptor antagonism decreases alcohol seeking in alcohol-dependent individuals.

Alcoholism, or alcohol use disorder, is a major public health concern that is a considerable risk factor for morbidity and disability; therefore, effective treatments are urgently needed. Here, we demonstrated that the glucocorticoid receptor (GR) antagonist mifepristone reduces alcohol intake in alcohol-dependent rats but not in nondependent animals. Both systemic delivery and direct administration into the central nucleus of the amygdala, a critical stress-related brain region, were sufficient to reduce alcohol consumption in dependent animals. We also tested the use of mifepristone in 56 alcohol-dependent human subjects as part of a double-blind clinical and laboratory-based study. Relative to placebo, individuals who received mifepristone (600 mg daily taken orally for 1 week) exhibited a substantial reduction in alcohol-cued craving in the laboratory, and naturalistic measures revealed reduced alcohol consumption during the 1-week treatment phase and 1-week post-treatment phase in mifepristone-treated individuals. Mifepristone was well tolerated and improved liver-function markers. Together, these results support further exploration of GR antagonism via mifepristone as a therapeutic strategy for alcoholism.

An open label trial of C-1073 (mifepristone) for psychotic major depression.

BACKGROUND: The rationale for treating patients with psychotic major depression (PMD) with glucocorticosteroid receptor (GR) antagonists is explained. METHODS: Thirty patients with PMD, with Hamilton Rating Scale for Depression (HAMD-21) scores of 18 or greater, were assigned in an open label trial to receive 50 mg, 600 mg, or 1200 mg of mifepristone for 7 days. RESULTS: All the subjects completed the protocol; there were no dropouts. Side effects were mild and sporadic. Of 19 subjects in the combined 600- and 1200-mg group, 13 had a 30% or greater decline in their Brief Psychiatric Rating Scale (BPRS) scores, compared with 4 of 11 in the 50-mg group. In the 600- and 1200-mg group, 12 of 19 subjects showed a 50% decline in the BPRS positive symptom subscale, a more sensitive index for the symptoms seen in PMD, compared with 3 of 11 in the 50-mg group; 8 of 19 subjects in the 600- and 1200-mg group had a 50% decline in the HAMD-21, compared with 2 of 11 in the 50-mg group. CONCLUSIONS: These results suggest that short term use of GR antagonists may be effective in the treatment of psychotic major depression and that further blinded studies are warranted.

Slowing the progression of cognitive decline in Alzheimer's disease using mifepristone.

High circulating levels of glucocorticoid hormones adversely affect cognition. Previous studies exploring the hypothalamic-pituitary-adrenal (HPA) axis and basal cortisol levels in the elderly reported that subjects with mid-range cortisol levels outperformed subjects with high cortisol levels on assessments of memory and attention. This study examines the efficacy of mifepristone, a glucocorticoid-antagonist, in decelerating the rate of cortisol-related cognitive decline in subjects with mile-to-moderate Alzheimer's disease (AD). Rate of cognitve decline is compared in AD subjects randomized to receive 200 mg of mifepristone daily for 6 mo or placebo. The Alzheimer's Disease Assessment Scale (ADAS) and the Folstein Mini Mental Status Exam (MMSE) will be the primary measures used to assess change in cognitve function over the 6 mo period, supplemented by a neuropsychological battery testing memory and language and reasoning skills. During each visit, subjects will have samples collected for determination of plasma adrenocorticotropin (ACTH), serum cortisol and salivary cortisol levels to assess HPA axis activity. The placebo arm of this study also investigate whether subjects with high baseline cortisol levels experience greater declines in cognitive impairment over time relative to subjects with Ad who have low baseline cortisol levels. Additionally, this study test the hypothesis that AD subjects with elevated cortisol at baseline will perform more poorly on neuropsychological exams that do subjects with low cortisol.

Effects of selective and non-selective glucocorticoid receptor II antagonists on rapid-onset diabetes in young rats.

The blockade of glucocorticoid (GC) action through antagonism of the glucocorticoid receptor II (GRII) has been used to minimize the undesirable effects of chronically elevated GC levels. Mifepristone (RU486) is known to competitively block GRII action, but not exclusively, as it antagonizes the progesterone receptor. A number of new selective GRII antagonists have been developed, but limited testing has been completed in animal models of overt type 2 diabetes mellitus. Therefore, two selective GRII antagonists (C113176 and C108297) were tested to determine their effects in our model of GC-induced rapid-onset diabetes (ROD). Male Sprague-Dawley rats (∼ six weeks of age) were placed on a high-fat diet (60%), surgically implanted with pellets containing corticosterone (CORT) or wax (control) and divided into five treatment groups. Each group was treated with either a GRII antagonist or vehicle for 14 days after surgery: CORT pellets (400 mg/rat) + antagonists (80 mg/kg/day); CORT pellets + drug vehicle; and wax pellets (control) + drug vehicle. After 10 days of CORT treatment, body mass gain was increased with RU486 (by ∼20% from baseline) and maintained with C113176 administration, whereas rats given C108297 had similar body mass loss (∼15%) to ROD animals. Fasting glycemia was elevated in the ROD animals (>20 mM), normalized completely in animals treated with RU486 (6.2±0.1 mM, p<0.05) and improved in animals treated with C108297 and C113176 (14.0±1.6 and 8.8±1.6 mM, p<0.05 respectively). Glucose intolerance was normalized with RU486 treatment, whereas acute insulin response was improved with RU486 and C113176 treatment. Also, peripheral insulin resistance was attenuated with C113176 treatment along with improved levels of ß-cell function while C108297 antagonism only provided modest improvements. In summary, C113176 is an effective agent that minimized some GC-induced detrimental metabolic effects and may provide an alternative to the effective, but non-selective, GRII antagonist RU486.

Acute effects of neonatal dexamethasone treatment on proliferation and astrocyte immunoreactivity in hippocampus and corpus callosum: towards a rescue strategy.

Dexamethasone (DEX), a synthetic glucocorticoid, has been used to treat respiratory distress syndrome in prematurely born infants. Despite the important short-term benefit on lung function, there is growing concern about the long-term outcome of this treatment, since follow-up studies of prematurely born infants have shown lasting adverse neurodevelopmental effects. Since the mechanism underlying these neurodevelopmental impairments is largely unknown, the aim of the present study was (i) to investigate the acute effects of neonatal DEX treatment on the developing brain; and (ii) to block specifically the effects of DEX on the brain by central administration of the glucocorticoid receptor (GR) antagonist mifepristone. Long Evans rat pups were injected subcutaneously with tapering doses of DEX or saline (SAL) on postnatal days (pnd) 1, 2 and 3. Separate groups received intracerebroventricular injections with mifepristone prior to DEX treatment. On pnd 4 and 10, pups were sacrificed and brains collected for analysis of cell proliferation (Ki-67) and astrogliosis (GFAP). We report that neonatal DEX treatment reduced hippocampal cell proliferation on pnd 4, an effect that was normalized by pnd 10. Although on pnd 4, GFAP expression was not affected, DEX treatment caused a significant reduction in the number and density of astrocytes in hippocampus and corpus callosum on pnd 10, which was normalized by mifepristone pre-treatment. These acute alterations in the neonate brain might underlie later functional impairments reported in DEX-treated animals and humans and further illustrate the impact of early GR activation on brain development.

Selective glucocorticoid receptor (type II) antagonists prevent weight gain caused by olanzapine in rats.

The use of antipsychotic medication has consistently been associated with serious side effects including weight gain and metabolic abnormalities. Strategies for mitigating these side effects have been tested, yet effective interventions have not been identified. The current study tested whether two recently identified selective glucocorticoid receptor antagonists would prevent weight gain induced by the antipsychotic olanzapine. Female Sprague-Dawley rats fed a normal chow diet were randomized (n=10 per group) to receive one of the following for 18days: vehicle, olanzapine plus vehicle (2.4mg/kg), olanzapine plus CORT 112716 (20mg/kg), olanzapine plus CORT 112716 (60mg/kg), olanzapine plus CORT 113083 (20mg/kg), or olanzapine plus CORT 113083 (60mg/kg). Rats receiving olanzapine plus CORT 112716 (60mg/kg) or olanzapine plus CORT 113083 (60mg/kg) gained significantly less weight than rats receiving only olanzapine. Both glucocorticoid receptor antagonists significantly attenuated the weight gain induced by olanzapine in a dose dependent manner. Differences in weight gain were not attributable to decreased food intake.