The importance of the endocrine environment in the initiation of the ageing process has been elucidated in several in vivo and in vitro studies. Changes in endocrine pathways accompany healthy ageing, these include the growth hormone/insulin-like growth factor-I axis (somatopause) and that of sexual hormones, namely estradiol (menopause), testosterone (andropause), and dehydroepiandrosterone and its sulphate (adrenopause). The clinical significance of these changes is variable and results in morphological and functional alterations of all organ systems including the skin and the central nervous system. Moreover, the pathogenesis of age-associated diseases such as epithelial skin cancer and neurodegenerative diseases has been partly attributed to the lack of hormones. Several studies have been conducted in an attempt to reverse the ageing process and clinical signs by substitution of the serum hormone levels in older individuals, however the benefits of hormone replacement therapy, if any, are still controversial. On the other hand, recent data suggest that skin is a window to the human organism and represents an adequate model for ageing research, also implying the use of skin samples for evaluating the ageing status of the central nervous system.

BACKGROUND

Chronic stress has been associated with detrimental or maladaptive neuroendocrine and immunological changes.

OBJECTIVE

We assessed the neuroendocrine and immunological correlates of a realistic chronic stress experienced by strictly healthy caregivers of Alzheimer's disease patients and age-matched controls.

METHODS

We screened 330 caregivers and 206 non-caregivers according to the 'strictly healthy' conditions established by the SENIEUR protocol. Forty-one strictly healthy caregivers (60.56 +/- 16.56 years) and 33 non-stressed controls (60.27 +/- 14.11 years) were selected for this study. Salivary cortisol and dehydroepiandrosterone sulfate (DHEAS) were assessed at multiple points by radioimmunoassay. Peripheral T cell proliferation and cellular sensitivity to glucocorticoids (corticosterone and dexamethasone, DEX) were evaluated by colorimetric assays. We also examined the hypothalamic-pituitary-adrenal (HPA) axis response to the administration of a low-dose DEX in vivo.

RESULTS

The caregivers were significantly more stressed, anxious and depressed than non-caregivers (all p < 0.0001), in contrast to similar cortisol levels. Caregivers had reduced DHEAS levels (-32%, p < 0.0001), an increased cortisol/DHEAS ratio (39.7%, p < 0.0001) and impaired HPA axis response to DEX intake. Caregivers had a higher T cell proliferation (p < 0.0001) and increased sensitivity to glucocorticoids in vitro (p < 0.01) as compared to non-stressed controls.

CONCLUSIONS

Our results suggest that the maintenance of health in chronically stressed populations may be associated with both protective and detrimental neuroendocrine and immunological changes.

BACKGROUND

In light of substantial sex differences in health outcomes, researchers need to focus on disentangling the underlying biological and social determinants. The objective of this study is to determine whether two populations that differ in many cultural and social dimensions--Taiwan and the United States--also vary with regard to sex differentials in biological markers of chronic disease.

METHODS

The analysis is based on three population-based surveys that include interviews, urine and blood specimens, and physical examinations: the Social Environment and Biomarkers of Aging Study (SEBAS) in Taiwan, the Wisconsin Longitudinal Survey (WLS), and the MacArthur studies of successful aging. The outcomes comprise six indicators of cardiovascular risk (total/high-density lipoprotein [HDL] cholesterol, HDL cholesterol, systolic and diastolic blood pressure, glycosylated hemoglobin, and waist/hip ratio) and four markers of sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA) axis functioning (epinephrine, norepinephrine, cortisol, and dehydroepiandrosterone sulfate [DHEA-S]).

RESULTS

U.S. males have significantly higher risk than females for all indicators of cardiovascular risk except glycosylated hemoglobin (p < 0.05). Sex differences are less consistent and smaller in Taiwan. Indicators of SNS and HPA axis functioning reveal a significant female disadvantage in both countries.

CONCLUSIONS

The analysis identifies important sex differences between Taiwan and the United States in biomarkers of cardiovascular risk that are consistent with cause of death data and may emanate from cultural and social differences between the two societies. The similarity of sex differences in SNS and HPA axis functioning across studies may reflect either stable sex differences in biological aging of these axes or commonalities in the social construction of gender-based responses to life experiences.

Insulin secretion is coupled with changes in β-cell metabolism. To define this process, 195 putative metabolites, mitochondrial respiration, NADP+, NADPH and insulin secretion were measured within 15 min of stimulation of clonal INS-1 832/13 β-cells with glucose. Rapid responses in the major metabolic pathways of glucose occurred, involving several previously suggested metabolic coupling factors. The complexity of metabolite changes observed disagreed with the concept of one single metabolite controlling insulin secretion. The complex alterations in metabolite levels suggest that a coupling signal should reflect large parts of the β-cell metabolic response. This was fulfilled by the NADPH/NADP+ ratio, which was elevated (8-fold; P<0.01) at 6 min after glucose stimulation. The NADPH/NADP+ ratio paralleled an increase in ribose 5-phosphate (>2.5-fold; P<0.001). Inhibition of the pentose phosphate pathway by trans-dehydroepiandrosterone (DHEA) suppressed ribose 5-phosphate levels and production of reduced glutathione, as well as insulin secretion in INS-1 832/13 β-cells and rat islets without affecting ATP production. Metabolite profiling of rat islets confirmed the glucose-induced rise in ribose 5-phosphate, which was prevented by DHEA. These findings implicate the pentose phosphate pathway, and support a role for NADPH and glutathione, in β-cell stimulus-secretion coupling.

BACKGROUND

Adrenal androgen excess is found in approximately 25-60% of women with polycystic ovary syndrome (PCOS), but the mechanisms underlying PCOS-related adrenal androgen excess are unclear.

OBJECTIVE

The objective of this study was to determine whether adrenal androgen excess is manifest in a nonhuman primate model for PCOS.

METHODS

Six prenatally androgenized (PA) and six control female rhesus monkeys of similar age, body weight, and body mass index were studied during d 2-6 of two menstrual cycles or anovulatory 30-d periods.

METHODS

Predexamethasone adrenal steroid levels were assessed in the first cycle (cycle 1). In a subsequent cycle (cycle 2), occurring one to three cycles after cycle 1, adrenal steroids were determined 14.5-16.0 h after an i.m. injection of 0.5 mg/kg dexamethasone (postdexamethasone levels) and after an i.v. injection of 50 microg ACTH-(1-39).

RESULTS

Both before and after dexamethasone, serum levels of dehydroepiandrosterone (DHEA) in PA females exceeded those in controls. After ACTH injection, PA females exhibited higher circulating levels of DHEA, androstenedione, and corticosterone but comparable levels of 17alpha-hydroxyprogesterone, cortisol, the sulfoconjugate of DHEA, and testosterone compared with controls.

CONCLUSIONS

Enhanced basal and ACTH-stimulated adrenal androgen levels in PA female monkeys may reflect up-regulation of 17,20 lyase activity in the adrenal zona reticularis, causing adrenal androgen excess comparable with that found in PCOS women with adrenal androgen excess. These findings open the possibility that PCOS adrenal hyperandrogenism may have its origins in fetal androgen excess reprogramming of adrenocortical function.

Dehydroepiandrosterone sulfate (DHEAS), the major circulating adrenal hormone, has been suggested to have a role in many aging related diseases and perhaps in aging itself. Its precise biologic effects are still unknown, and data on healthy people over 90 yr of age are not available. We measured serum DHEAS levels in 75 healthy subjects aged 90-106 yr of both sexes and searched for correlations between DHEAS and several endocrine-metabolic parameters (serum thyroid hormones, GH-insulin-like-growth factor I (GH-IGF-I) axis, serum lipid profile, anthropometric indices of body composition) of the same subjects. The resulting data, normalized by logarithmic transformation (geometric mean at age 90-99, 551 ng/mL in men, 364 ng/mL in women; at age>> 100 yr, 404 ng/mL in men, 521 ng/mL in women) resulted five-fold lower than DHEAS levels measured in a young control group (geometric mean at < 40 yr of age, 3110 ng/mL in men, 2824 ng/mL in women). In women over ninety yr, DHEAS was positively correlated with serum free triodothyronine (FT3) levels (r = 0.34, P = 0.05) and inversely with triglycerides (r = -0.45, P = 0.05). In men over 90 yr, DHEAS had positive correlations with body mass index (r = 0.41, P < 0.03) and waist-to-hip ratio (r = 0.47, P < 0.01) taken as indices of body's energy reserves (fat). To determine whether low serum DHEAS levels predict poor functional status in the very old, the Activity Daily Living (ADL) test was administered in all over-ninety subjects. Men with the highest functioning levels had the highest DHEAS levels (P < 0.03). Our data suggest that DHEAS levels may influence and/or be influenced by several endocrine and metabolic features of oldest-old people, depending on the sexual steroid milieu. DHEAS seems also to have a strong interrelation with functional activities. A favorable role for DHEAS in successful aging is proposed.

There are few data on the biological correlates of female antisocial behavior. This study compared adrenal androgen and gonadal hormone levels in adolescent girls with conduct disorder (CD) to girls without any psychiatric disorder (NC). We studied 87 girls, (47 CD; 36 NC), ages 15-17 years, obtaining three blood samples, drawn 20 min apart between 8 and 9 AM in the first 72 h of the onset of menstrual flow. Plasma was assayed for testosterone, estradiol, androstenedione, dehydroepiandrosterone (DHEA), dehydroepiandrosterone-sulfate (DHEA-S), sex hormone binding globulin (SHBG), and cortisol; area under the curve (AUC) for each of the three samples was used in the data analysis. We also calculated the Free Testosterone Index, Free Estrogen Index, Index of Hyperandrogenism and cortisol to DHEA ratio. In addition to receiving a full psychiatric interview, each girl completed a self-report questionnaire on general aggression. Main hormone analyses controlled for potentially confounding variables such as psychiatric comorbidity and race. Girls with CD had significantly lower cortisol to DHEA ratios, but did not differ from NC girls on any other hormone variable. Girls with symptoms of aggressive CD had significantly higher mean free testosterone indexes, lower SHBG levels, and lower cortisol to DHEA ratios than girls with non-aggressive CD. Girls with CD scored higher on the aggression questionnaire, but there was no association between general aggression and any hormone variable for the sample. Our data suggest that girls with CD, particularly aggressive CD, have lower cortisol to DHEA ratios, higher levels of free testosterone, and lower levels of SHBG. Clinical and research implications of these findings are discussed.

OBJECTIVE

To evaluate whether treatment with prasterone (dehydroepiandrosterone [DHEA]) would allow the dosage of prednisone (or an equivalent corticosteroid) to be reduced to < or = 7.5 mg/day for 2 months or longer while maintaining stable or reduced disease activity in steroid-dependent women with systemic lupus erythematosus (SLE).

METHODS

In a double-blind, randomized trial, 191 female SLE patients receiving prednisone (10-30 mg/day) were treated daily with either placebo, 100 mg of oral prasterone (an adrenal androgen), or 200 mg of oral prasterone for 7-9-months. At monthly intervals, corticosteroid dosages were reduced by algorithm in patients whose SLE Disease Activity Index (SLEDAI) score was stable or improved. Patients for whom a sustained reduction in the dosage of prednisone (< or = 7.5 mg/day) was achieved for at least the last 2 months of the 7-9-month treatment period were classified as responders.

RESULTS

Response rates were 41% in the placebo group, 44% in the 100-mg prasterone group, and 55% in the 200-mg group (P = 0.110, 200 mg versus placebo). Among the 137 subjects (45 in the placebo group, 47 in the 100-mg group, and 45 in the 200-mg group) who had active disease at baseline (defined as SLEDAI score >2), 29%, 38%, and 51%, respectively, were responders (P = 0.031 for 200 mg prasterone versus placebo). Acne was the most common adverse event but was generally mild. Clinical and laboratory changes primarily reflected androgenic effects of prasterone.

CONCLUSIONS

Among women with lupus disease activity, reducing the dosage of prednisone to < or = 7.5 mg/day for a sustained period of time while maintaining stabilization or a reduction of disease activity was possible in a significantly greater proportion of patients treated with oral prasterone, 200 mg once daily, compared with patients treated with placebo.

BACKGROUND

This study evaluated the efficacy of the adrenal androgen, dehydroepiandrosterone, in the treatment of midlife-onset dysthymia.

METHODS

A double-blind, randomized crossover treatment study was performed as follows: 3 weeks on 90 mg dehydroepiandrosterone, 3 weeks on 450 mg dehydroepiandrosterone, and 6 weeks on placebo. Outcome measures consisted of the following. Cross-sectional self-ratings included the Beck Depression Inventory, and visual analogue symptom scales. Cross-sectional objective ratings included the Hamilton Depression Rating Scale, the Cornell Dysthymia Scale and a cognitive test battery. Seventeen men and women aged 45 to 63 years with midlife-onset dysthymia participated in this study. Response to dehydroepiandrosterone or placebo was defined as a 50% reduction from baseline in either the Hamilton Depression Rating Scale or the Beck Depression Inventory.

RESULTS

In 15 patients who completed the study, a robust effect of dehydroepiandrosterone on mood was observed compared with placebo. Sixty percent of the patients responded to dehydroepiandrosterone at the end of the 6-week treatment period compared with 20% on placebo. A significant response was seen after 3 weeks of treatment on 90 mg per day. The symptoms that improved most significantly were anhedonia, loss of energy, lack of motivation, emotional "numbness," sadness, inability to cope, and worry. Dehydroepiandrosterone showed no specific effects on cognitive function or sleep disturbance, although a type II error could not be ruled out.

CONCLUSIONS

This pilot study suggests that dehydroepiandrosterone is an effective treatment for midlife-onset dysthymia.

Evidence that neurosteroids have anxiolytic effects in animal models of anxiety has suggested that alterations of neurosteroid secretion might be implicated in the pathogenetic mechanisms of anxiety disorders in humans. In 25 female patients with panic disorder (PD) and 11 healthy female controls, we measured plasma concentrations of progesterone (PROG), pregnenolone (PREG), allopregnanolone (3alpha,5alpha-tetrahydroprogesterone=3alpha,5alpha-THPROG), dehydroepiandrosterone (DHEA) and tetrahydrodeoxycorticosterone (3alpha,5alpha-THDOC) during a drug-free month and during the following month of paroxetine therapy. The neurosteroids were measured during the early follicular phase, the mid-luteal phase and the premenstrual phase of both months (days 7, 22 and 27 from the beginning of the cycle). Significantly higher levels in patients than controls were found in PROG during the mid-luteal phase of both months, PREG in the premenstrual phase in the drug-free month, 3alpha,5alpha-THPROG during the follicular phase of the drug-free month and during the premenstrual phase of the therapy month, and 3alpha,5alpha-THDOC during the premenstrual phases of both months. DHEA levels did not differ in patients and controls. These results suggest that neurosteroids in PD are hypersecreted, possibly as an attempt to counteract the anxiogenic underlying hyperactivity of the hypothalamo-pituitary-adrenal axis and to improve a reduced GABA(A) receptor sensitivity.

To determine if dehydroepiandrosterone (DHEA) replacement improves insulin secretion, insulin action, and/or postprandial glucose metabolism, 112 elderly subjects with relative DHEA deficiency ingested a labeled mixed meal and underwent a frequently sampled intravenous glucose tolerance test before and after 2 years of either DHEA or placebo. Despite restoring DHEA sulphate concentrations to values observed in young men and women, the changes over time in fasting and postprandial glucose concentrations, meal appearance, glucose disposal, and endogenous glucose production were identical to those observed after 2 years of placebo. The change over time in postmeal and intravenous glucose tolerance test insulin and C-peptide concentrations did not differ in men treated with DHEA or placebo. In contrast, postmeal and intravenous glucose tolerance test change over time in insulin and C-peptide concentrations were greater (P < 0.05) in women after DHEA than after placebo. However, since DHEA tended to decrease insulin action, the change over time in disposition indexes did not differ between DHEA- and placebo-treated women, indicating that the slight increase in insulin secretion was a compensatory response to a slight decrease in insulin action. We conclude that 2 years of replacement of DHEA in elderly men and women does not improve insulin secretion, insulin action, or the pattern of postprandial glucose metabolism.

BACKGROUND

Dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) decrease with aging and are important androgen and estrogen precursors in older adults. Declines in DHEAS with aging may contribute to physiological changes that are sex hormone dependent.

OBJECTIVE

The aim was to determine whether DHEA replacement increases bone mineral density (BMD) and fat-free mass.

METHODS

A randomized, double-blinded, controlled trial was conducted at an academic research institution. Participants were 70 women and 70 men, aged 60-88 yr, with low serum DHEAS levels.

METHODS

The intervention was oral DHEA 50 mg/d or placebo for 12 months.

METHODS

BMD, fat mass, and fat-free mass were measured before and after intervention.

RESULTS

Intent-to-treat analyses revealed trends for DHEA to increase BMD more than placebo at the total hip (1.0%, P = 0.05), trochanter (1.2%, P = 0.06), and shaft (1.2%, P = 0.05). In women only, DHEA increased lumbar spine BMD (2.2%, P = 0.04; sex-by-treatment interaction, P = 0.05). In secondary compliance analyses, BMD increases in hip regions were significant (1.2-1.6%; all P < 0.02) in the DHEA group. There were no significant effects of DHEA on fat or fat-free mass in intent-to-treat or compliance analyses.

CONCLUSIONS

DHEA replacement therapy for 1 yr improved hip BMD in older adults and spine BMD in older women. Because there have been few randomized, controlled trials of the effects of DHEA therapy, these findings support the need for further investigations of the benefits and risks of DHEA replacement and the mechanisms for its actions.

The dehydroepiandrosterone (DHEA) concentration decreases with age. There is evidence that DHEA has a protective effect against age-related disorders, including cardiovascular disease. Accordingly, we examined the effect of DHEA supplementation (25 mg/d) on endothelial function, insulin sensitivity, and fibrinolytic activity in 24 men with hypercholesterolemia (mean age, 54 +/- 1 yr). All subjects were enrolled in a randomized, double-blind study. Flow-mediated dilation of brachial artery after transient occlusion, which was expressed as the percent change from the baseline value of the diameter, increased significantly with DHEA supplementation [DHEA: baseline, 3.9 +/- 0.5%; 4 wk, 6.9 +/- 0.7%; 8 wk, 7.9 +/- 0.6%; 12 wk, 8.4 +/- 0.7% (P < 0.01 vs. baseline for all, by ANOVA); placebo: 4.1 +/- 0.6%, 4.5 +/- 0.5%, 3.9 +/- 0.5%, and 4.4 +/- 0.6% (P < 0.01 for all, by ANOVA)]. There was a significant concurrent reduction in the plasma levels of plasminogen activator inhibitor type 1 during DHEA supplementation [DHEA: 9.1 +/- 2.2, 6.4 +/- 2.3, 5.5 +/- 2.8, and 5.1 +/- 2.0 IU/ml (P < 0.01 vs. baseline, by ANOVA); placebo: 9.0 +/- 2.1, 10.4 +/- 2.2, 9.5 +/- 2.2, and 9.6 +/- 2.1 IU/ml (P < 0.01, by ANOVA)]. DHEA supplementation also decreased steady state plasma glucose [DHEA: baseline, 178.9 +/- 12.2; 12 wk, 132.0 +/- 12.8 mg/dl (P < 0.01, by ANOVA); placebo: 181.0 +/- 13.8 and 179.6 +/- 12.4 mg/dl (P < 0.01, by ANOVA)]. In contrast, steady state plasma insulin did not change during the study in either group. The low dose DHEA supplementation improves vascular endothelial function and insulin sensitivity and decreases the plasminogen activator inhibitor type 1 concentration. These beneficial changes have the potential to attenuate the development of age-related disorders such as cardiovascular disease.

Bone health, characterized by its mass, density, and micro-architectural qualities, is maintained by a balanced system of remodeling. The lack of these qualities, caused by an uncoupling of the remodeling process, leads to bone fragility and an increased risk for fracture. The prime regulator of bone remodeling is the RANK/RANKL/OPG system. The common origin of both bone and immune stem cells is the key to understanding this system and its relationship to the transcription factor nuclear factor kappaB in bone loss and inflammation. Via this coupled osteo-immune relationship, a catabolic environment from heightened proinflammatory cytokine expression and/or a chronic antigen-induced activation of the immune system can initiate a switch-like diversion of osteoprogenitor-cell differentiation away from monocyte-macrophage and osteoblast cell formation and toward osteoclast and adipocyte formation. This disruption in bone homeostasis leads to increased fragility. Dietary and specific nutrient interventions can reduce inflammation and limit this diversion. Common laboratory biomarkers can be used to assess changes in body metabolism that affect bone health. This literature review offers practical information for applying effective strategic nutrition to fracture-risk individuals while monitoring metabolic change through serial testing of biomarkers. As examples, the clinician may recommend vitamin K and potassium to reduce hypercalciuria, _-lipoic acid and N-acetylcysteine to reduce the bone resorption marker N-telopeptide (N-Tx), and dehydroepiandrosterone (DHEA), whey, and milk basic protein (the basic protein fraction of whey) to increase insulin-like growth factor-1 (IGF-1) and create a more anabolic profile.

A new oral contraceptive has been developed that contains a unique progestogen, drospirenone (DRSP), and that has both antiandrogenic and antimineralocorticoid activity. Our objective was to compare the effect of 30 microg ethinyl estradiol (EE)/3 mg DRSP (EE/DRSP; Yasmin, Schering AG, Berlin, Germany) with that of 35 microg EE/2 mg cyproterone acetate (EE/CPA; Diane-35, Schering AG, Berlin, Germany) on mild-to-moderate cases of acne. Diane-35 is used worldwide (it is not on the market in the United States and Japan) as a hormone treatment for acne, with additional contraceptive benefits. This multicenter, double-blind, randomized study was completed over 9 treatment cycles. A total of 128 women with mild-to-moderate facial acne, with or without seborrhea and/or hirsutism, were randomized. Treatment with either EE/DRSP or EE/CPA was assigned in a 2:1 ratio. Acne lesions, sebum production, and hair growth on the upper lip, chin, and chest were assessed, as well as levels of total and free testosterone, androstenedione, dehydroepiandrosterone sulfate (DHEAS), sex hormone-binding globulin (SHBG), and luteinizing hormone (LH). At study completion, dermatologists, gynecologists, and subjects gave their overall assessment of the effect of treatment on acne. After 9 treatment cycles, the median total acne lesion count was reduced markedly by 62.5% in the EE/DRSP group and 58.8% in the EE/CPA group. A comparison of the 2 groups revealed that EE/DRSP was at least as effective as EE/CPA. Both preparations also reduced sebum production and hair growth on the upper lip and chin. A 3-fold increase in the levels of SHBG was observed in both treatment groups, and levels of androgens and LH decreased. Treatment differences were not seen. Subjective evaluation of the effect of treatment on facial acne by dermatologists, gynecologists, and the subjects themselves indicated an excellent or good improvement for most subjects in both groups. EE/DRSP has been shown to be as effective for treating mild-to-moderate acne as a preparation containing EE/CPA. This new preparation may provide useful hormone therapy for women with androgen-dependent disorders who also require contraception.

The rat central nervous system (CNS) has previously been shown to synthesize pregnenolone (PREG) and convert it to progesterone (PROG) and 7 alpha-hydroxy-PREG (7 alpha-OH PREG). Astrocytes, which participate to the regulation of the CNS function, might be involved in the metabolism of neurosteroids. Purified type 1 astrocytes were obtained from fetal rat forebrain with the use of selective culture conditions and were identified by immunostaining with specific antibodies (GFAP+, A2B5-). They were plated at low, intermediate, or high densities (2.5-5 x 10(5), 1-2 x 10(6), or 4-8 x 10(6) cells/dish, respectively) and maintained for 21 d. They were then incubated with 14C-PREG and 14C-DHEA for 24 h and the steroids extracted from cells and media were analyzed. Most radioactive derivatives were released into incubation media. Two metabolic pathways were mainly observed. PREG and DHEA were oxidized to PROG and androstenedione (ADIONE), respectively, [3 beta-hydroxysteroid-dehydrogenase, delta 5-->4 3-ketosteroid-isomerase (3 beta-HSD) activity], and converted to 7 alpha-OH PREG and 7 alpha-OH DHEA, respectively (7 alpha-hydroxylase activity). After low density plating, the formation of PROG and ADIONE was approximately 10% of incubated radioactivity, tenfold larger than that of 7 alpha-hydroxylated metabolites. In contrast, after high density plating, low levels of PROG and ADIONE were formed, whereas the conversion to either 7 alpha-OH PREG or 7 alpha-OH DHEA was>> or = 50%. The results expressed per cell indicated that the 3 beta-HSD activity was almost completely inhibited at high cell density, in contrast to the 7 alpha-hydroxylation which was maintained or increased. The pattern of steroid metabolism was related to cell density at the time of measurement and not to an early commitment of cells: when primary cultures were plated at high density (8 x 10(6) cells/dish), then subcultured after several dilutions (3-, 9-, or 27-fold), the 3 beta-HSD activity was recovered only at low density. Furthermore, when 5 x 10(5) cells were centrifuged and the resulting clusters were plated, 3 beta-HSD activity was decreased, whereas steroid 7 alpha-hydroxylation was enhanced. This implies that cell density per se, but neither cell number nor a diffusible factor(s) is involved in the regulation of steroid metabolism. We conclude that astrocytes in culture metabolize PREG and DHEA, and that the metabolic conversions and, therefore, the related enzymatic activities depend on cell-to-cell contacts.(ABSTRACT TRUNCATED AT 400 WORDS)

We have isolated three novel organic anion transporter cDNAs designated rat GST-1 (gonad-specific transporter), rat GST-2, and human GST, expressed at high levels in the testis. Rat GST-1, GST-2, and human GST consist of 748, 702, and 719 amino acids, respectively, and all molecules possess the 12 predicted transmembrane domains, which is a common structure of organic anion transporters. Northern blot analyses and in situ hybridization revealed that both of the rat molecules are highly expressed in the testis, especially in Sertoli cells, spermatogonia, and Leydig cells. Weak signals are also detected in the epididymis and ovary in adult rat. The exclusive expression of human GST mRNA in the testis was confirmed by RT-PCR. The pharmacological experiments of Xenopus laevis oocytes injected with the respective rat GST-1- and GST-2-cRNAs revealed that both rat GST-1 and GST-2 transport taurocholic acid, dehydroepiandrosterone sulfate, and T4 with Michaelis-Menten kinetics (taurocholic acid, Km = 8.9 and 2.5 microm, dehydroepiandrosterone sulfate, Km = 25.5 and 21.microm, and T4, Km = 6.4 and 5.8 for rat GST-1 and GST-2, respectively). T3 was also transported by rat GST-1 and GST-2. These data suggest that rat GST-1 and GST-2 might be one of the molecular entities responsible for transporting dehydroepiandrosterone sulfate and thyroid hormones involved in the regulation of sex steroid transportation and spermatogenesis in the gonad.

The mechanisms causing the rise in adrenal androgen production during the course of adrenarche remain to be defined. However, the increase in steroid release is clearly associated with a series of intra-adrenal changes in the expression of steroidogenic enzymes needed for dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) production, as well as an expansion of the adrenal zona reticularis (ZR). We and others have defined the adrenal expression pattern of key steroidogenic enzymes during adrenarche. As adrenarche proceeds, the expanding ZR expresses greater levels of cytochrome b5 (CYB5) and steroid sulfotransferase (SULT2A1) than the adjacent fasciculata. In contrast, the growing ZR is deficient in 3beta-hydroxysteroid dehydrogenase type 2 (HSD3B2). The resulting profile of steroidogenic enzymes lends itself to the production of adrenal androgens and appears to track the progression of adrenarche. This article reviews the intra-adrenal changes of the adrenal cortex associated with adrenarche.

Neurosteroids are important endogenous regulators of gamma-aminobutryic acid (GABA(A)) and N-methyl-D-aspartate (NMDA) receptors and also influence neuronal morphology and function. Neurosteroids are produced in the brain using many of the same enzymes found in the adrenal and gonad. The crucial enzyme for the synthesis of DHEA (dehydroepiandrosterone) in the brain is cytochrome P450c17. The transcriptional strategy for the expression of P450c17 is clearly different in the brain from that in the adrenal or gonad. We previously characterized a novel transcriptional regulator from Leydig MA-10 cells, termed StF-IT-1, that binds at bases -447/-399 of the rat P450c17 promoter, along with the known transcription factors COUP-TF (chicken ovalbumin upstream promoter transcription factor), NGF-IB (nerve growth factor inducible protein B), and SF-1 (steroidogenic factor-1). We have now purified and sequenced this protein from immature porcine testes, identifying it as the nuclear phosphoprotein SET; a role for SET in transcription was not established previously. Binding of bacterially expressed human and rat SET to the DNA site at -418/-399 of the rat P450c17 gene transactivates P450c17 in neuronal and in testicular Leydig cells. We also found SET expressed in human NT2 neuronal precursor cells, implicating a role in neurosteroidogenesis. Immunocytochemistry and in situ hybridization in the mouse fetus show that the ontogeny and distribution of SET in the developing nervous system are consistent with SET being crucial for initiating P450c17 transcription. SET's developmental pattern of expression suggests it may participate in the early ontogenesis of the nervous, as well as the skeletal and hematopoietic, systems. These studies delineate an important new factor in the transcriptional regulation of P450c17 and consequently, in the production of DHEA and sex steroids.

Dehydroepiandrosterone (DHEA) is the major adrenal steroid of young adults; however, its physiologic functions, if any, are not known. The purpose of this review is to evaluate the current literature in which DHEA was administered to either humans or experimental animals to discern what these functions might be. Reports are divided into five areas: neurologic, immunologic, cardiovascular, oncologic, and metabolic. Particular attention is paid to the dosage and route of administration. This type of analysis shows that at the lowest doses, DHEA has effects on neurologic and immunologic tissues, suggesting that these two sites may be physiologic targets. DHEA also affects cardiologic and metabolic functions as well as tumor growth, but such actions require higher doses and may reflect 'pharmacologic' activities. It is proposed that DHEA's pattern of activity represents a new class of steroid hormones, the "Regnantoids." Further progress in the endocrinology of this family of steroids may only come when synthetic, long-acting analogs of DHEA are available for in vitro studies to allow correlations between hormone action and receptor binding.

Current therapy of pulmonary arterial hypertension (PAH) is inadequate. Dehydroepiandrosterone (DHEA) effectively treats experimental pulmonary hypertension in chronically hypoxic and monocrotaline-injected rats. Contrary to these animal models, SU5416/hypoxia/normoxia-exposed rats develop a more severe form of occlusive pulmonary arteriopathy and right ventricular (RV) dysfunction that is indistinguishable from the human disorder. Thus, we tested the effects of DHEA treatment on PAH and RV structure and function in this model. Chronic (5 wk) DHEA treatment significantly, but moderately, reduced the severely elevated RV systolic pressure. In contrast, it restored the impaired cardiac index to normal levels, resulting in an improved cardiac function, as assessed by echocardiography. Moreover, DHEA treatment inhibited RV capillary rarefaction, apoptosis, fibrosis, and oxidative stress. The steroid decreased NADPH levels in the RV. As a result, the reduced reactive oxygen species production in the RV of these rats was reversed by NADPH supplementation. Mechanistically, DHEA reduced the expression and activity of Rho kinases in the RV, which was associated with the inhibition of cardiac remodeling-related transcription factors STAT3 and NFATc3. These results show that DHEA treatment slowed the progression of severe PAH in SU5416/hypoxia/normoxia-exposed rats and protected the RV against apoptosis and fibrosis, thus preserving its contractile function. The antioxidant activity of DHEA, by depleting NADPH, plays a central role in these cardioprotective effects.

We used data from a cross-sectional study of 107 premenopausal women to evaluate the relation of age, menarcheal age, parity, and age at first live birth with plasma estrogen and androgen levels in premenopausal women. Fasting blood specimens were collected on each of days 5-7, 12-15, and 21-23 of menstrual cycles of the participants and pooled to create follicular, midcycle, and luteal phase samples, respectively, for each woman. Age was associated significantly and positively with plasma estradiol levels during the follicular phase [percentage difference/year = 2.6; 95% confidence interval (CI) = 1.0-4.2] and midcycle (percentage difference/year = 2.7; 95% CI = 0.9-4.7) but not the luteal phase (percentage difference/year = -0.4; 95% CI = -1.9-1.3) of the menstrual cycle. The relation of age to plasma estradiol varied by parity, with significant interactions during midcycle and luteal phase. Among nulliparous women, plasma estradiol levels increased with age midcycle and during the luteal phase, but among parous women estradiol levels decreased with age during these phases of the menstrual cycle. Plasma estrone increased with age in all women during the follicular phase of the menstrual cycle (percentage difference/year = 1.5; 95% CI = 0.2-2.8). During the luteal phase there was a significant interaction with parity; estrone levels in nulliparous women varied only slightly with age, but levels in parous women decreased significantly as age increased. The androgens, androstenedione and dehydroepiandrosterone sulfate decreased, and sex hormone-binding globulin increased as age increased. The results of this cross-sectional study suggest that pregnancy may modify age-related changes in plasma estrogen levels.

Adrenal function was studied in 2 groups of intensive care unit (ICU) patients with varying degrees of illness, as determined by Acute Physiological and Chronic Health Evaluation (APACHE). The 15 seriously ill patients with high APACHE scores (greater than or equal to 25) had elevated Therapeutic Intervention Scores and increased mortality compared to the 15 ill patients (APACHE, less than or equal to 10; 67% vs. 27%). Plasma cortisol, aldosterone, and androstenedione concentrations were increased in the ICU patients compared to those in normal subjects (n = 23), being greater in the seriously ill patients. Plasma dehydroepiandrosterone sulfate (DHEAS) concentrations were low in both groups of ICU patients. The ratios of aldosterone or androstenedione to cortisol were not altered, whereas the DHEAS to cortisol ratios were reduced in the ICU patients. ACTH injection elicited increases in plasma cortisol, aldosterone, and androstenedione concentrations in both groups of ICU patients, and the ratios of aldosterone and androstenedione to cortisol did not change. In the seriously ill patients, plasma DHEAS increased, so that the DHEAS to cortisol ratio did not change, whereas in less ill patients plasma DHEAS did not increase, so that the DHEAS to cortisol ratio was reduced. In this study of patients admitted to an ICU, impairment of adrenal steroid secretion appears to be specific for DHEAS. Although plasma cortisol was elevated in ill patients proportional to the degree of illness, the contribution of the concomitant decrease in DHEAS to this increase is not clear.

Pregnenolone (P) and dehydroepiandrosterone (D) accumulate in the brain as unconjugated steroids and their sulfate (S) and fatty acid (L) esters. The microsomal acyl-transferase activity is highest in immature (1-3 weeks old) male rats. The immunocytochemical and biochemical evidence for P biosynthesis by differentiated oligodendrocytes is reviewed. The importance of P synthesis for its brain accumulation is assessed by the intracysternal injection of the inhibitor aminoglutethimide. Primary glial cell cultures convert P to 20-OH-P, PL, progesterone, 5 alpha-pregnane-3,20-dione and 3 alpha-hydroxy-5 alpha-pregnane-20-one (Polone). Astroglial cell cultures also produce these metabolites, whereas neurons from 17-day mouse embryos only form 20-OH-P. P and D are converted to the corresponding 7 alpha-hydroxylated metabolites by a very active P-450 enzyme from rat brain microsomes. Several functions of neurosteroids are documented. P decreases in olfactory bulb of intact male rats exposed to the scent of estrous females. D inhibits the aggressive behavior of castrated male mice towards lactating female intruders. The D analog 3 beta-methyl-androst-5-en-17-one, which cannot be metabolized into sex steroids and is not demonstrably androgenic or estrogenic is at least as efficient as D. Both compounds elicit a marked decrease of PS in rat brain. The Cl- conductance of gamma-aminobutyric (GABAA) receptor is stimulated by GABA agonists, an effect which is enhanced by Polone and antagonized by PS. Thus, P metabolites in brain as well as steroids of extraencephalic sources may be involved physiologically in GABAA receptor function. The neurosteroids accumulated in brain may be precursors of sex steroid hormones and progesterone receptors have been localized in glial cells. P and D do not bind to any known intracellular receptor. A heat stable P binding protein has been found in brain cytosol with distinct ligand specificity. A binding component specific for steroids sulfates, including Polone S, DS and PS, in the order of decreasing affinity is localized in adult rat brain synaptosomal membranes. Its relationship to the GABAA receptor is under current investigation.