Circulatory neurosteroid levels in underweight female adolescent anorexia nervosa inpatients and following weight restoration

Nineteen female adolescent inpatients diagnosed with anorexia nervosa, restricting type (AN-R) and 16 non-eating disordered (ED) controls were assessed for plasma dehydroepiandrosterone (DHEA), dehydroepiandrosterone-sulphate (DHEA-S), and cortisol levels, and for eating-related and non-eating-related psychopathology. AN-R patients were assessed at admission, 1 month and 4 months following hospitalization. The non-ED controls were assessed once. No baseline between-group differences were found in plasma cortisol, DHEA, and DHEA-S levels, whereas the patient group had a significantly lower Cortisol/DHEA-S ratio and elevated scores on most psychopathological parameters. A significant increase was found in the body mass index of the AN-R patients at 4 months post-hospitalization, accompanied by a decrease in plasma cortisol levels and a trend towards decreased Cortisol/DHEA and Cortisol/DHEA-S ratios, whereas no change occurred in psychopathology. The difference in Cortisol/DHEA-S ratio between AN-R patients and non-ED controls, and the different patterns of change in cortisol vs. DHEA(-S) levels following weight restoration, may in part account for the feeding difficulties in AN, particularly during refeeding.     

钩吻素子抗焦虑作用及其对海马区神经甾体水平的影响

目的：进一步明确钩吻素子的抗焦虑作用并探讨其对大鼠海马区神经甾体水平的影响。方法以地西泮为阳性对照药,大鼠高架十字迷宫为动物模型,评价钩吻素子的抗焦虑活性及特点;采用固相萃取结合高效液相色谱-质谱联用技术测定大鼠海马区中神经甾体的含量。结果与空白对照组相比,钩吻素子不影响大鼠在高架十字迷宫中的总入臂次数（ P＞0.05）,并且能显著增加大鼠进入开臂次数和在开臂的停留时间百分率（P＜0.01）。钩吻素子处理组大鼠海马区孕烯醇酮和别孕烯醇酮含量较空白对照组显著增高（P＜0.05）。结论钩吻素子具有抗焦虑作用,其作用机制可能与提高海马区神经甾体孕烯醇酮和别孕烯醇酮水平有关。     

The specificity of stress responses to different nocuous stimuli: neurosteroids and depression

The role that adrenal cortex and neurosteroid hormones may have in the etiology and/or maintenance of depressive diseases is discussed. Selye's concept of stress as the summation of unspecific body responses of the autonomic central nervous system (CNS) and hypothalamic pituitary adrenal axis (HPAA) as the main characteristic of it is contrasted with Mason's view of stress responses as being specific for different stimuli, i.e., the neuroendocrine system responds with the production of a hormonal profile individualized and characteristic for the various stimuli applied. The data reviewed provides support for Mason's interpretation of stress as fundamentally a behavioral response. In turn, the high relevance of emotional factors in the determination of stress responses led to a reconsideration of cognitive-affective interactions in nervous systems. Recent results revealed that improvement in depression treated with antidepressants (ADs) is associated with an increase in the neurosteroid 3alpha 5alpha tetrahydroprogesterone, both in the blood and cerebrospinal fluid of recovered patients. The increase occurs with both selective serotonin reuptake inhibitors and tricyclic ADs. An evaluation of the possible and putative roles for neurosteroids in the CNS is presented and suggestions for enhancing the type of supporting data from the laboratory diagnosis of depressions are advanced.     

Estradiol and testosterone modulate the anesthetic action of the GABA-A agonist THIP,but not of the neurosteroid 3α,5β-pregnanolone in the rat

Rationale As sex steroids modify the number and distribution of brain -aminobutyric acid (GABA)_A receptor subunits, we investigated the potential modulation of anesthesia, induced by agents acting on the GABA_A receptor, by estrogen and androgen.Objectives To assess possible effects of sex and hormonal condition (i.e., intact vs castrate; estradiol vs testosterone treatment) on the anesthetic effect of a GABA_A agonist, THIP (4,5,6,7-tetrahydroisoxazolo[5,4,-c]pyridin-3-ol hydrochloride), and an allosteric modulator of the GABA_A receptor: 3-hydroxy-5-pregnan-20-one (epipregnanolone).Methods The potencies of THIP and epipregnanolone for inducing loss of the righting response were compared between: (a) female and male rats; (b) intact and castrated animals of each sex; (c) untreated castrates and castrates given estradiol or testosterone.Results Sex and endocrine condition influenced sensitivity to i.v. THIP for the induction of anesthesia. ED₅₀ values were: gonadectomized females, 80 mg/kg > intact males, 50 mg/kg > proestrous females, 35 mg/kg > gonadectomized males, 28 mg/kg. Estradiol benzoate (EB; 3 g/day for 5 days) significantly increased THIP sensitivity in gonadectomized females: THIP + EB: ED₅₀=26 mg/kg vs THIP + sesame oil: ED₅₀=94 mg/kg, while testosterone propionate (TP; 10 mg injected 24 h before THIP) decreased THIP sensitivity in orchidectomized males when compared with vehicle-injected animals (ED₅₀=72 mg/kg vs 22 mg/kg, respectively).Conclusions Results suggest that estrogen increases the density or availability of GABA_A receptor subtypes on which THIP acts, while testosterone exerts the opposite effect. Neither sex nor gonadal condition influenced the anesthetic action of epipregnanolone as a similar potency was found in intact and in gonadectomized males and females.     

Neurosteroid biosynthetic pathways changes in prefrontal cortex in Alzheimer's disease

Expression of the genes for enzymes involved in neurosteroid biosynthesis was studied in human prefrontal cortex (PFC) in the course of Alzheimer's disease (AD) (n = 49). Quantitative RT-PCR (qPCR) revealed that mRNA levels of diazepam binding inhibitor (DBI), which is involved in the first step of steroidogenesis and in GABAergic transmission, were increased, as were mRNA levels for several neurosteroid biosynthetic enzymes. Aromatase, 17β-hydroxysteroid dehydrogenase type 1 (HSD17B1) and aldo-keto reductase 1C2 (AKR1C2), were all increased in the late stages of AD. Several GABA-A subunits were significantly reduced in AD. Increased expression of aromatase in the PFC was confirmed by immunohistochemistry and was found to be localized predominantly in astrocytes. These data suggest a role for estrogens and allopregnanolone produced by astrocytes in the PFC in AD, possibly as part of a rescue program. The reduced gene expression of some synaptic and extra-synaptic GABA-A subunits may indicate a deficit of modulation of GABA-A receptors by neuroactive steroids, which may contribute to the neuropsychiatric characteristics of this disease.     

Depression-like behavior of aged male and female mice is ameliorated with administration of testosterone or its metabolites

There may be a role of age-related decline in androgen production and/or its metabolism for late-onset depression disorders of men and women. Thus, the anti-depressant-like effects of testosterone (T) and its metabolites are of interest. Given that these androgens have disparate mechanisms of action, it is important to begin to characterize and compare their effects in an aged animal model. We hypothesized that there would be sex differences in depression behavior of aged mice and that androgens would reduce depression-like behaviors in the forced swim test. To investigate this, male and female mice (~ 24 months old) were subcutaneously administered T, or one of its 5α-reduced metabolites (dihydrotesterone-DHT, 5α-androstane,17β-diol-3α-diol), or aromatized metabolite (estradiol — E₂), or oil vehicle. Mice were administered androgens (1 mg/kg) 1 h before being tested in the forced swim test, an animal model of depression. We found that males spent more time immobile, and less time swimming, than females. Administration of T, DHT, or 3α-diol similarly reduced time spent immobile, and increased time spent struggling, of male and female mice. E₂, compared to vehicle administration, decreased time spent immobile of males and females, but increased time spent swimming of females and time spent struggling of male mice. Together, these data suggest that T and its 5α-reduced and aromatized metabolites have anti-depressant-like effects in aged male and female mice.     

Discriminative stimulus effects of ethanol and 3α-hydroxy-5α-pregnan-20-one in relation to menstrual cycle phase in cynomolgus monkeys (Macaca fascicularis)

 The present study was designed to characterize the discriminative stimulus effects of ethanol and the neurosteroid 3α-hydroxy-5α-pregnan-20-one (allopregnanolone) in nonhuman primates as a function of menstrual cycle phase. Female cynomolgus monkeys (Macaca fascicularis) were trained in a two-lever procedure to discriminate 1.0 g/kg ethanol (IG, 30 min pretreatment) from water using food reinforcement. A cumulative dosing procedure was used to assess changes in the potency of ethanol and an endogenous anxiolytic steroid in the follicular versus the luteal phase of the menstrual cycle. Plasma progesterone and allopregnanolone levels were determined within 24 h of testing to verify phase of menstrual cycle. The monkeys were more sensitive to the discriminative stimulus effects of ethanol and the ethanol-like effects of the endogenous neuroactive steroid allopregnanolone during the luteal phase of the menstrual cycle. These findings suggest that changes in the endogenous levels of ovarian-derived progesterone and allopregnanolone alter sensitivity to the discriminative stimulus effects of ethanol. Received: 13 March 1996 / Final version: 26 September 1996     

Effects of Chronic Ethanol Consumption and Withdrawal on the Neuroactive Steroid 3α-Hydroxy-5α-pregnan-20-one in Male and Female Rats

Prolonged alcohol (ethanol) consumption leads to the development of alcohol tolerance and cross-tolerance to some benzodiazepines and barbiturates. In contrast, rats undergoing alcohol withdrawal are sensitized to the anticonvulsant effects of the endogenous GABAA receptor modulator, 3α-hydroxy-5α-pregnan-20-one (3α, 5α-THP). Alterations in endogenous, cerebral cortical levels of 3α, 5α-THP during alcohol withdrawal could contribute to the observed sensitization to 3α, 5α-THP. Therefore, this study investigated plasma and brain levels of 3α,5α-THP, progesterone, and corticosterone during alcohol dependence and withdrawal in the rat. Plasma corticosterone, progesterone (a precursor of 3α,5α-THP) and 3α,5α-THP levels were unchanged in alcohol-dependent animals. Cerebral cortical levels of 3α,5α-THP decreased in dependent male animals, but not in dependent female rats. During alcohol withdrawal, plasma corticosterone and progesterone levels increased in male, but not female rats. However, neither plasma nor cerebral cortical 3α,5α-THP levels were altered from control levels in male or female rats during alcohol withdrawal. Plasma and brain levels of 3α,5α-THP were markedly higher in female compared with male rats. Cerebral cortical levels of 3α,5α-THP during the diestrus phase of the estrus cycle were ˜4 to 6 ng/g, a concentration that may approach physiological relevance. These findings suggest that sensitization to 3α,5α-THP during alcohol withdrawal is not mediated by elevations in brain levels of endogenous 3α,5α-THP in male or female rats. However, elevations in circulating corticosterone and progesterone levels during ethanol withdrawal in male rats may underlie gender differences in allopreg-nanolone sensitivity during ethanol withdrawal.