Thymus as a target tissue of glucocorticoid action: what are the consequences of glucocorticoids thymectomy?

Glucocorticoids represent the most powerful endogenous anti-inflammatory and immunosuppressive effectors, interfering with virtually every step of immunoinflammatory responses. Glucocorticoids are often the most effective therapy in the prevention or suppression of inflammation and other immunologically mediated processes, but their use is limited by systemic side effects induced by the over-production of reactive oxygen species, causing dysregulation of physiological processes. The thymus is an organ with both endocrine and immune functions. Glucocorticoids induce thymocyte apoptosis, causing a profound reduction in thymic mass and volume and inducing hormonal thymectomy. The clinical aspects of glucocorticoid thymectomy are not under enough investigation. These unwanted systemic side effects may be the consequence of prolonged therapeutic application of glucocorticoids and prolonged or chronic activation of the hypothalamic-pituitary adrenal axis, which may lead to increased and prolonged secretion of glucocorticoids. This review will discuss the metabolic effects of glucocorticoids in the context of thymic physiology asthe primary sex hormone-responsive organ.

Sex differences in drug-related stress-system changes: implications for treatment in substance-abusing women

Extensive research indicates that chronic substance abuse disrupts stress and reward systems of the brain. Gender variation within these stress-system alterations, including the impact of sex hormones on these changes, may influence sex-specific differences in both the development of, and recovery from, dependency. As such, gender variations in stress-system function may also provide a viable explanation for why women are markedly more vulnerable than men to the negative consequences of drug use. This article therefore initially reviews studies that have examined gender differences in emotional and biophysiological changes to the stress and reward system following the acute administration of drugs, including cocaine, alcohol, and nicotine. The article then reviews studies that have examined gender differences in response to various types of stress in both healthy and drug-abusing populations. Studies examining the impact of sex hormones on these gender-related responses are also reported. The implications of these sex-specific variations in stress and reward system function are discussed in terms of both comorbid psychopathology and treatment outcome.

Effects of light therapy on sleep, mood, and temperature in women with nonseasonal major depression

Research has supported the applicability and efficacy of light therapy in the treatment of nonseasonal depression. The investigators examined the effects of light therapy on sleep, core temperature, depressed mood, and perception of fatigue and energy in a sample of pre-menopausal and post-menopausal women diagnosed with nonseasonal, nonbipolar depression. Women were randomly assigned to either light therapy (n = 16) or placebo (n = 13) for a 28-day period. Pre and post measures of sleep and core temperature were collected. In addition, measures of depressed mood, fatigue, and energy were collected throughout the study period. Significant changes in depression and energy were found in the treatment group, but not in the placebo group. There was a significant reduction in the temperature mesor and less wake time during the first third of the sleep period in the treatment group but not in the placebo group. Light therapy yielded significant improvement in depression when compared with placebo intervention and core temperature mesor returned to normal. There was no significant phase shift, perhaps due in part to the absence of any baseline circadian phase disturbances. Relationships between temperature, sleep, depressed mood, fatigue, and energy variables offer potential directions for future research and clinical intervention.

Lack of efficacy of estradiol for depression in postmenopausal women: a randomized, controlled trial

BACKGROUND

Estrogen has been considered as a potential antidepressant in postmenopausal women. Our goal was to study whether estrogen therapy is effective in treating depressive disorders in older postmenopausal women and to determine whether progestins are associated with a deterioration of mood.

METHODS

After 2 weeks of single-blind placebo treatment in 87 patients, 57 were randomly assigned to receive 8 weeks of treatment with estradiol (.1 mg/day; n = 31) or placebo (n = 26). All patients were then treated with medroxyprogesterone 10 mg/day for 2 weeks combined with the study patch. Depressive symptoms were rated with the 21-item Hamilton Depression and Center for Epidemiologic Studies Depression scales.

RESULTS

A clinically significant antidepressant effect of estradiol was excluded after 8 weeks of estradiol treatment. The estradiol group and placebo group improved in depressive symptoms at a similar rate based on the Hamilton Depression Scale (40% decreases in depression for estradiol vs. 44% for placebo). No significant increase in depressive symptoms was demonstrated with the use of progestins; however, positive affect decreased slightly with the use of combined estradiol-medroxyprogesterone compared with medroxyprogesterone alone (5.8%, p =.027).

CONCLUSIONS

Estradiol cannot be considered as an effective treatment in postmenopausal women with mild to moderate depression.

Gender and gonadal hormone effects in the olfactory bulbectomy animal model of depression

Major depressive disorder (MDD) affects women to a greater extent then men; however, the few studies that have examined the role of gender in an animal model of depression have shown inconsistent results. The purpose of the present study was to determine if the gonadal hormone milieu of the animal modulated behavioral changes following olfactory bulbectomy (OBX), a well-documented animal model of depression. Body weight, sucrose preference levels and open-field activity levels were measured once a week for a period of 2 weeks in gonadally intact and gonadectomized male and female rats. Following these baseline measurements, animals underwent either OBX or sham surgery. Body weight, sucrose preference and activity levels were assessed for 4 weeks post-OBX surgery. OBX-gonadectomized animals exhibited higher activity levels than OBX gonadally intact and control animals. This effect of gonadectomy was more robust in males. OBX-females (both intact and gonadectomized) exhibited significantly lower sucrose preference levels than OBX-males (both intact and gonadectomized) and control animals. These results suggest that the gonadal hormone milieu of the animal plays a role in modulating sucrose preference and activity levels following OBX.