Dehydroepiandrosterone decreases serum tumor necrosis factor-alpha and restores insulin sensitivity: independent effect from secondary weight reduction in genetically obese Zucker fatty rats

Low serum dehydroepiandrosterone is associated with diabetic dyslipidemia risk in males with type 2 diabetes

Objective

Sex steroid hormones are associated with the advancement of metabolic diseases such as dyslipidemia. This cross-sectional study aimed to investigate the relationship between dehydroepiandrosterone, dehydroepiandrosterone sulfate, androstenedione, and testosterone levels and the risk of dyslipidemia in people with type 2 diabetes mellitus.

Materials and Methods

The analysis included 1,927 patients with type 2 diabetes mellitus. Serum dehydroepiandrosterone, dehydroepiandrosterone sulfate, androstenedione, and testosterone levels were determined using lipid chromatography-tandem mass spectrometry. Multivariable analyses were performed to investigate the association between the variables and dyslipidemia.

Results

The multivariable-adjusted odds ratio (OR) and 95% confidence interval (CI) of dyslipidemia across DHEA tertiles were 0.39 and 0.24-0.64, respectively (p trend = 0.001). This relationship was still maintained when analyzed as a continuous variable (odds ratio, 0.96; 95% confidence interval, 0.92-0.99; P < 0.01). However, in males with type 2 diabetes mellitus, no significant correlations were found between rising levels of dehydroepiandrosterone sulfate, androstenedione, and total testosterone and the risk of dyslipidemia (all P > 0.05). Furthermore, there was no significant association between androgen precursors and total testosterone with regard to the risk of developing dyslipidemia (all P > 0.05).

Conclusions

Serum dehydroepiandrosterone levels were substantially and adversely correlated with dyslipidemia in adult men with T2DM. These results indicated that dehydroepiandrosterone may have an essential role in the development of dyslipidemia. More prospective research is required to validate this link.

Role of the Sodium-Dependent Organic Anion Transporter (SOAT/SLC10A6) in Physiology and Pathophysiology

The sodium-dependent organic anion transporter (SOAT, gene symbol SLC10A6) specifically transports 3'- and 17'-monosulfated steroid hormones, such as estrone sulfate and dehydroepiandrosterone sulfate, into specific target cells. These biologically inactive sulfo-conjugated steroids occur in high concentrations in the blood circulation and serve as precursors for the intracrine formation of active estrogens and androgens that contribute to the overall regulation of steroids in many peripheral tissues. Although SOAT expression has been detected in several hormone-responsive peripheral tissues, its quantitative contribution to steroid sulfate uptake in different organs is still not completely clear. Given this fact, the present review provides a comprehensive overview of the current knowledge about the SOAT by summarizing all experimental findings obtained since its first cloning in 2004 and by processing SOAT/SLC10A6-related data from genome-wide protein and mRNA expression databases. In conclusion, despite a significantly increased understanding of the function and physiological significance of the SOAT over the past 20 years, further studies are needed to finally establish it as a potential drug target for endocrine-based therapy of steroid-responsive diseases such as hormone-dependent breast cancer.

DHEA and Its Metabolites Reduce the Cytokines Involved in the Inflammatory Response and Fibrosis in Primary Biliary Cholangitis

Dehydroepiandrosterone (DHEA) is an abundant steroid and precursor of sex hormones. During aging, the reduction in DHEA synthesis causes a significant depletion of estrogens and androgens in different organs, such as the ovaries, brain, and liver. Primary Biliary Cholangitis (PBC) is a cholestatic liver disease that begins with immune-mediated bile duct damage, and is followed by liver fibrosis, and finally, cirrhosis. PBC primarily affects postmenopausal women, with an average age of diagnosis of 65 years, but younger women are also affected. Here, we analyzed the levels of DHEA, estradiol (E2), and estriol (E3) in the PBC sera of females at an age of diagnosis under 40 (n = 37) and above 65 (n = 29). Our results indicate that in PBC patients at an age of diagnosis under 40, E2 was significantly lower compared to that in healthy women. In contrast, the levels of DHEA and E3 were in a normal range. Furthermore, ELISA assays revealed that in PBC patients at an age of diagnosis above 65, the levels of DHEA, E2, and E3 significantly declined in comparison to those in younger patients. In addition, flow cytometry analysis showed that the level of IL-8 significantly decreased while the level of TNF-α increased in older PBC patients compared to younger ones. Moreover, we showed for the first time that the sulfonated form of DHEA, DHEA-S, reduces the levels of both pro-inflammatory interleukins, IL-8 and TNF-α, in PBC-like cholangiocytes (H69-miR506), while it diminishes the level of the pro-fibrotic interleukin, IL-13, in hepatocytes (Hep-G2). Finally, we demonstrated that the expression of the pro-fibrotic agent TGF-β significantly increased in both the early (F0–F3) and cirrhotic (F4) stages of PBC, and this elevation was accompanied by higher α-SMA expression.

Immune disturbances in female genital tuberculosis and latent genital tuberculosis

BACKGROUND

Female genital tuberculosis (FGTB), an important clinical sub-type of extra-pulmonary tuberculosis (EPTB) is responsible for about 10% cases of infertility in India. Both FGTB and latent genital tuberculosis (LGTB) can cause infertility through blockage of fallopian tubes and through altered uterine endometrial receptivity.

AIMS

This review tries to elucidates the role of various immune factors in FGTB and LGTB.

CONTENT

Various immune disturbances are observed in FGTB and LGTB like growth factors and cytokines which inhibit implantation and several inflammatory signaling pathways like mitogen activated protein kinase (MAPK), natural killer (NK) cells, nuclear factor kappa-B (NF-KB), tumor necrosis factor (TNF), and toll like receptors (TLR) signaling are dysregulated. These altered immune factors and pathways may be detected in the endometrial biopsies at the early stages of disease before permanent damage. Prompt and adequate treatment with the four anti-tubercular drugs (rifampicin [R], isoniazid [H], pyrazinamide [Z], and ethambutol [E]) can increase pregnancy rates in some of these women. Assisted reproduction especially in-vitro fertilization and embryo transfer may be required for some women.

IMPLICATIONS

Inflammatory pathways identified from the gene profiling have enabled development of potential biomarkers for early diagnosis of FGTB. Immunomodulation and novel biotechniques like stem cell transplantation, nanoparticles and host directed therapies are being tried in selected patients of FGTB and LGTB with promising results.

Functions of dehydroepiandrosterone in relation to breast cancer

Although DHEA sulfate (DS) is the most abundant steroid in the circulation, breast fluid contains an approximately 80-fold greater concentration than serum. Transport of DS into cells requires organic anion transporting polypeptides (OATPs), which are specific for cell type, cell location, and substrate, but may have a broader specificity for housekeeping functions. Specific classes, which may be modified by soluble factors including neutral steroids, have been identified in the breast. After transport, DS may be cleaved to DHEA by ubiquitous sulfatases, which may be modified by the cell milieu, or DHEA may enter by diffusion. Synthesis from cholesterol does not occur because CYP17B12 and cytochrome b5 are lacking in breast tissues. Case-control studies reveal a positive association of serum DS with risk of breast cancer. The association is even greater with DHEA, particularly in postmenopausal women with HR + invasive tumors. Metabolites of DHEA, androstenedione and testosterone, are associated with breast cancer but DHEA is likely to have an independent role as well. Mechanisms by which DHEA may promote breast cancer relate to its effect in increasing circulating IGF-I, by inhibiting the suppressive effect of glucocorticoids, and by promoting retention of pre-adipocytes with aromatase activity. In addition, DHEA may interact with the G-protein coupled receptor GPER for stimulation of miR-21 and subsequent activation of the MAPK pathway. DHEA also has antitumor properties that relate to stimulation of immunity, suppression of inflammation, and elevation of adipose tissue adiponectin synthesis. The net effect may depend on the which factors predominate.

Cortisol-dehydroepiandrosterone ratios are inversely associated with hippocampal and prefrontal brain volume in schizophrenia

While high levels of glucocorticoids are generally neuro-damaging, a related adrenal steroid, dehydroepiandrosterone (DHEA), has anti-glucocorticoid and neuroprotective properties. Previous work has shown increased circulating levels of DHEA and abnormal cortisol/DHEA ratios in people with schizophrenia, however reports are limited and their relationship to neuropathology is unclear. We performed the largest study to date to compare levels of serum DHEA and cortisol/DHEA ratios in people with schizophrenia and healthy controls, and investigated the extent to which cortisol/DHEA ratios predict brain volume. Serum cortisol and DHEA were assayed in 94 people with schizophrenia and 81 healthy controls. T1-weighted high-resolution anatomical scans were obtained using a 3 T Achieva scanner on a subset of 59 people with schizophrenia and 60 healthy controls. Imaging data were preprocessed and analyzed using SPM12. People with schizophrenia had significantly increased serum DHEA levels (p = 0.002), decreased cortisol/DHEA ratios (p = 0.02) and no difference in cortisol levels compared to healthy controls. Cortisol/DHEA ratios were inversely correlated with hippocampal (r = -0.33 p = 0.01) and dorsolateral prefrontal cortex (r = -0.30, p = 0.02) volumes in patients. Our findings suggest that the cortisol/DHEA ratio may be a molecular blood signature of hippocampal and cortical damage. These results further implicate the role of DHEA and hypothalamic-pituitary-adrenal axis dysfunction in the pathophysiology of schizophrenia.

Brown Adipose Transplantation Improves Polycystic Ovary Syndrome-Involved Metabolome Remodeling

Polycystic ovary syndrome (PCOS) is a complex reproductive, endocrine, and metabolic disorder in reproductive-age women. In order to explore the active metabolites of brown adipose tissue (BAT) transplantation in improving the reproductive and metabolic phenotypes in a PCOS rat model, the metabolites in the recipient's BAT were explored using the liquid chromatography-mass spectrometry technique. In total, 9 upregulated and 13 downregulated metabolites were identified. They were roughly categorized into 12 distinct classes, mainly including glycerophosphoinositols, glycerophosphocholines, and sphingolipids. Ingenuity pathway analysis predicted that these differentially metabolites mainly target the PI3K/AKT, MAPK, and Wnt signaling pathways, which are closely associated with PCOS. Furthermore, one of these differential metabolites, sphingosine belonging to sphingolipids, was randomly selected for further experiments on a human granulosa-like tumor cell line (KGN). It significantly accelerated the apoptosis of KGN cells induced by dihydrotestosterone. Based on these findings, we speculated that metabolome changes are an important process for BAT transplantation in improving PCOS. It might be a novel therapeutic target for PCOS treatment.

Dehydroepiandrosterone on metabolism and the cardiovascular system in the postmenopausal period

Dehydroepiandrosterone (DHEA), mostly present as its sulfated ester (DHEA-S), is an anabolic hormone that naturally declines with age. Furthermore, it is the most abundant androgen and estrogen precursor in humans. Low plasma levels of DHEA have been strongly associated with obesity, insulin resistance, dyslipidemia, and high blood pressure, increasing the risk of cardiovascular disease. In this respect, DHEA could be regarded as a promising agent against metabolic syndrome (MetS) in postmenopausal women, since several age-related metabolic diseases are reported during aging. There are plenty of experimental evidences showing beneficial effects after DHEA therapy on carbohydrate and lipid metabolism, as well as cardiovascular health. However, its potential as a therapeutic agent appears to attract controversy, due to the lack of effects on some symptoms related to MetS. In this review, we examine the available literature regarding the impact of DHEA therapy on adiposity, glucose metabolism, and the cardiovascular system in the postmenopausal period. Both clinical studies and in vitro and in vivo experimental models were selected, and where possible, the main cellular mechanisms involved in DHEA therapy were discussed. Schematic representation showing some of the general effects observed after administration DHEA therapy on target tissues of energy metabolism and the cardiovascular system. ↑ represents an increase, ↓ represents a decrease, - represents a worsening and ↔ represents no change after DHEA therapy.

Androgen profile in young females with insulin resistance; the importance of 17-Hydroxyprogesterone

Considerable researches on sex steroids and insulin action have suggested a mutual interaction between hyperandrogenemia and insulin resistance (IR). The objective of present study was to evaluate the androgens levels in young females with emphasis on the association of 17OHP with IR. Serum concentrations of glucose, insulin, and androgens in 80 young females were measured by standard routine procedures. Total testosterone (TT), dihydrotestosterone (DHT), dehydroepiandrosterone sulfate (DHEAS), androstenedione (ASD), and 17-hydroxyprogesterone (17OHP) levels were higher in patients with IR compared to healthy controls (p < .05). 17OHP was associated with IR and other androgens tested in young females. According to the results, androgen excess was associated with IR in young females and TT appeared to be independent predictor of IR in these patients. These data may suggest that simultaneous quantification of an androgen profile including at least TT, DHT, and 17OHP can present useful clinical information for assessment of androgen excess.

Central intracrine DHEA synthesis in ageing-related neuroinflammation and neurodegeneration: therapeutic potential?

It is a well-known fact that DHEA declines on ageing and that it is linked to ageing-related neurodegeneration, which is characterised by gradual cognitive decline. Although DHEA is also associated with inflammation in the periphery, the link between DHEA and neuroinflammation in this context is less clear. This review drew from different bodies of literature to provide a more comprehensive picture of peripheral vs central endocrine shifts with advanced age—specifically in terms of DHEA. From this, we have formulated the hypothesis that DHEA decline is also linked to neuroinflammation and that increased localised availability of DHEA may have both therapeutic and preventative benefit to limit neurodegeneration. We provide a comprehensive discussion of literature on the potential for extragonadal DHEA synthesis by neuroglial cells and reflect on the feasibility of therapeutic manipulation of localised, central DHEA synthesis.

Effect of Dehydroepiandrosterone (DHEA) on Diabetes Mellitus and Obesity

Type 2 diabetes is a metabolic disorder that is characterized by an impaired capacity to secrete insulin, insulin resistance, or both. Dehydroepiandrosterone (DHEA), a steroid hormone produced by the adrenal cortex, has been reported to have beneficial effects on diabetes mellitus and obesity in animal models. DHEA and DHEA-sulfate (DHEA-S) have been reported to increase not only insulin secretion of the pancreas but also insulin sensitivity of the liver, adipose tissue, and muscle. We investigated the effects of DHEA on glucose metabolism in animal models and reported decrease of liver gluconeogenesis. Recently, we reported the effect of DHEA on the liver and muscle by using insulin-stimulated insulin receptor substrate 1 and 2 (IRS1 and IRS2)-deficient mice. DHEA increased Akt phosphorylation in the liver of C57BL6 IRS1- and IRS2-deficient mice fed with a high-fat diet (HFD), which suggests that the increase in DHEA-induced Akt signaling is sufficient in the presence of IRS1 or IRS2. In addition, other studies have also reported the effect of DHEA on diabetes mellitus in the liver, muscle, adipose tissue, and pancreatic β-cell and its effect on obesity in animal models. A meta-analysis in elderly men and women has found that DHEA supplementation has no effects on blood glucose levels. However, DHEA supplementation to patients with type 2 diabetes has not been fully elucidated. Therefore, further studies are needed to provide greater insight into the effect of DHEA on diabetes and obesity in animal and human models.

Tuberculosis, the Disrupted Immune-Endocrine Response and the Potential Thymic Repercussion As a Contributing Factor to Disease Physiopathology

Upon the pathogen encounter, the host seeks to ensure an adequate inflammatory reaction to combat infection but at the same time tries to prevent collateral damage, through several regulatory mechanisms, like an endocrine response involving the production of adrenal steroid hormones. Our studies show that active tuberculosis (TB) patients present an immune-endocrine imbalance characterized by an impaired cellular immunity together with increased plasma levels of cortisol, pro-inflammatory cytokines, and decreased amounts of dehydroepiandrosterone. Studies in patients undergoing specific treatment revealed that cortisol levels remained increased even after several months of initiating therapy. In addition to the well-known metabolic and immunological effects, glucocorticoids are involved in thymic cortical depletion with immature thymocytes being quite sensitive to such an effect. The thymus is a central lymphoid organ supporting thymocyte T-cell development, i.e., lineage commitment, selection events and thymic emigration. While thymic TB is an infrequent manifestation of the disease, several pieces of experimental and clinical evidence point out that the thymus can be infected by mycobacteria. Beyond this, the thymic microenvironment during TB may be also altered because of the immune-hormonal alterations. The thymus may be then an additional target of organ involvement further contributing to a deficient control of infection and disease immunopathology.

Effect of dehydroepiandrosterone (DHEA) on Akt and protein kinase C zeta (PKCζ) phosphorylation in different tissues of C57BL6, insulin receptor substrate (IRS)1(-/-), and IRS2(-/-) male mice fed a high-fat diet

We have previously reported that dehydroepiandrosterone (DHEA) suppresses the activity and mRNA expression of the hepatic gluconeogenic enzyme glucose-6-phosphatase (G6Pase), and hepatic glucose production in db/db mice. Tyrosine phosphorylation levels of Insulin receptor substrate (IRS)1 and IRS2 reportedly differ between the liver and muscle tissue and the effect of DHEA on insulin signaling has not been elucidated. Therefore, we examined DHEA's effect on the liver and muscle tissue of IRS1(-/-) and IRS2(-/-) mice. Eight-week-old male C57BL6, IRS1(-/-), and IRS2(-/-) mice were fed a high-fat diet (HFD), or an HFD containing 0.2% DHEA for 4 weeks. In a separate experiment, 8-week-old male C57BL6 mice were fed an HFD or an HFD containing 0.2% androstenedione for 4 weeks. In an insulin tolerance test, DHEA administration decreased the initial plasma glucose levels in the C57BL6, IRS1(-/-), and IRS2(-/-) mice but did not decrease the ratios to the basal blood glucose level. Although DHEA administration increased Akt phosphorylation in the liver of the C57BL6, IRS1(-/-), and IRS2(-/-) mice, androstenedione administration did not increase Akt phosphorylation in the liver of C57BL6 mice. DHEA administration did not increase Akt and PKCζ phosphorylation in the muscle tissue of C57BL6, IRS1(-/-), or IRS2(-/-) mice. However, androstenedione administration increased Akt and PKCζ phosphorylation in the muscle tissue of C57BL6 mice. These findings suggest that the effect of DHEA on insulin action in the liver is self-mediated by DHEA or DHEA sulfate (DHEA-S) in the presence of IRS1, IRS2, or both.

Serum Dehydroepiandrosterone Sulfate and Risk for Type 2 Diabetes in Older Men and Women: The Pro.V.A Study

OBJECTIVE

A large body of clinical data suggests the importance of endogenous sex hormones in the pathogenesis of diabetes, but very little is known about the possible relationship between dehydroepiandrosterone sulfate (DHEAS) and diabetes, particularly in the elderly. We aimed, therefore, to examine whether high serum levels of DHEAS have any protective effects on the incidence of type 2 diabetes and to elucidate the possible role of gender in a cohort of older subjects.

METHODS

We followed 1258 community-dwelling subjects aged ≥65 years without type 2 diabetes who belonged to the Progetto Veneto Anziani (Pro.V.A.) for 4.4±1.2 years. DHEAS were measured at baseline and categorized into gender-specific tertiles. The incidence of type 2 diabetes was diagnosed in cases of fasting plasma glucose above 7.0 nmol/L, glycated hemoglobin ≥6.5%, use of glucose-lowering drugs or a 2-hour postload blood sugar level ≥11.1 nmol/L during the follow-up period.

RESULTS

Although no significant differences in potential risk factors for diabetes were apparent across DHEAS tertiles at the baseline in either gender, when those with lower DHEAS were taken for reference, Cox regression analysis showed that males in the highest DHEAS tertile had lower risks for being diagnosed with diabetes during the follow up (HR=0.23; 95% CI: 0.11-0.51; p<0.0001), whereas no significant differences emerged across DHEAS tertiles for females or for the sample as a whole.

CONCLUSIONS

Higher serum DHEAS levels revealed a significant protective effect against the onset of type 2 diabetes in older men but not in older women, confirming different sensitivities of type 2 diabetes to DHEAS between genders.

Effect of Electroacupuncture on Inflammation in the Obese Zucker Fatty Rat Model of Metabolic Syndrome

Chronic inflammation is known to be associated with visceral obesity and insulin resistance and is characterized by altered levels of production of adipokines such as tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), IL-6, leptin, and adiponectin. Metabolic syndrome (MetS) is a major and escalating public health and clinical challenge worldwide, and patients with MetS have an increased risk of developing cardiovascular disease and type 2 diabetes mellitus. Electroacupuncture (EA) was tested as a means of decreasing inflammation in genetically obese Zucker fatty rats, which serve as a model of MetS. Repeated application of EA at the Zhongwan/Guanyuan acupoints decreased serum TNF-α, but produced no significant alterations in serum leptin, adiponectin, or IL-10. EA had no significant effect on the levels of these four adipokines in white adipose tissue. These findings are consistent with the supposition that EA inhibits proliferation and/or infiltration of macrophages into the adipose tissue of obese rats and stimulates the release of IL-10 from the decreased numbers of macrophages present in adipose tissue. Compared with the control animals, no significant change in body weight occurred. The blood glucose (BG) level over a 30-minute interval in Week 2 was relatively the same as that in Week 1, suggesting that EA treatment does not increase the likelihood of developing hyperglycemia.

Hyperandrogenism induces a proinflammatory TNFα response to glucose ingestion in a receptor-dependent fashion

CONTEXT

Hyperandrogenism and inflammation are related in polycystic ovary syndrome (PCOS). Hyperandrogenemia can induce inflammation in reproductive-age women, but the mechanism for this phenomenon is unclear.

OBJECTIVE

We examined the in vivo and in vitro effects of hyperandrogenism on mononuclear cell (MNC)-derived androgen receptor (AR) status and TNFα release.

DESIGN

This study combined a randomized, controlled, double-blind protocol with laboratory-based cell culture experiments.

SETTING

This work was performed in an academic medical center.

PARTICIPANTS

Lean, healthy, reproductive-age women were treated with 130 mg of dehydroepiandrosterone (DHEA) or placebo (n = 8 subjects each) for 5 days and also provided untreated fasting blood samples (n = 12 subjects) for cell culture experiments.

MAIN OUTCOME MEASURES

AR mRNA content and TNFα release were measured before and after DHEA administration in the fasting state and 2 hours after glucose ingestion. TNFα release in the fasting state was also measured in cultured MNCs exposed to androgens with or without flutamide preincubation.

RESULTS

At baseline, subjects receiving DHEA or placebo exhibited no significant difference in androgens and TNFα release from MNCs before and after glucose ingestion. Compared with placebo, DHEA administration raised levels of T, androstenedione, and DHEA sulfate, and increased MNC-derived AR mRNA content and TNFα release in the fasting state and in response to glucose ingestion. Compared with MNC exposure to baseline concentrations of DHEA (175 ng/dL) or T (50 ng/dL), the absolute change in TNFα release increased after exposure to T concentrations of 125 and 250 ng/dL and a DHEA concentration of 1750 ng/dL. Preincubation with flutamide reduced the TNFα response by ≥ 60% across all T concentrations.

CONCLUSION

Androgen excess in vivo and in vitro comparable to what is present in PCOS increases TNFα release from MNCs of lean healthy reproductive-age women in a receptor-dependent fashion. Hyperandrogenemia activates and sensitizes MNCs to glucose in this population.

Association of serum dehydroepiandrosterone sulfate and cognition in older adults: sex steroid, inflammatory, and metabolic mechanisms

OBJECTIVE

Dehydroepiandrosterone sulfate (DHEAS) levels and cognitive function decline with age, and a role for DHEAS in supporting cognition has been proposed. Higher DHEAS levels may be associated with better cognitive performance, although potential mechanisms for this relationship are not well established.

METHOD

We performed a cross-sectional study of the relationship between serum DHEAS and three aspects of cognition--executive function, working memory, and processing speed--in 49 men and 54 women, aged 60-88 years, with low serum DHEAS levels. We examined three potential mechanisms of DHEAS action--sex hormone sufficiency, inflammatory status, and glucose regulation.

RESULTS

After adjustment for multiple covariates, higher serum DHEAS levels were associated with better working memory (standardized beta coefficient 0.50, p < .05), with a trend toward better executive function (standardized beta coefficient 0.37, p < .10) in men only. There was a nonsignificant trend toward a negative association between levels of tumor necrosis factor α (TNFα) and working memory in the combined population (standardized beta coefficient -0.22, p < .10). None of the glucoregulatory measures was associated with cognitive function.

CONCLUSIONS

The relationship between DHEAS and cognition is complex and differs by sex and cognitive domain. This study supports the need for further investigations of the sex-specific effects of DHEAS on cognition and its underlying mechanisms of action.

Hyperandrogenism sensitizes leukocytes to hyperglycemia to promote oxidative stress in lean reproductive-age women

CONTEXT

Hyperandrogenism and oxidative stress are related in polycystic ovary syndrome (PCOS), but it is unknown whether hyperandrogenemia can activate oxidative stress.

OBJECTIVE

The purpose of this study was to determine the effect of oral androgen administration on fasting and glucose-stimulated leukocytic reactive oxygen species (ROS) generation, reduced nicotinamide adenine dinucleotide phosphate oxidase p47(phox) subunit gene expression, and plasma thiobarbituric acid-reactive substances (TBARS) in lean healthy reproductive-age women.

PARTICIPANTS, DESIGN, AND SETTING

Sixteen lean healthy ovulatory reproductive-age women were treated with 130 mg dehydroepiandrosterone (DHEA) or placebo (n = 8 each) for 5 d in this randomized, controlled, double-blind study that was performed at an an academic medical center.

MAIN OUTCOME MEASURES

Leukocytic ROS generation, p47(phox) gene expression, and plasma TBARS were quantified in the fasting state and 2 h after glucose ingestion, before and after treatment.

RESULTS

Before treatment, subjects receiving DHEA or placebo exhibited no differences in androgens or any prooxidant markers while fasting and after glucose ingestion. Compared with placebo, DHEA administration raised levels of testosterone, androstenedione, and DHEA-sulfate, increased the percent change in glucose-challenged p47(phox) RNA content, and increased the percent change in fasting and glucose-challenged ROS generation from mononuclear cells and polymorphonuclear cells, p47(phox) protein content, and plasma TBARS.

CONCLUSION

Elevation of circulating androgens comparable to what is present in PCOS increases leukocytic ROS generation, p47(phox) gene expression, and plasma TBARS to promote oxidative stress in lean healthy reproductive-age women. Thus, hyperandrogenemia activates and sensitizes leukocytes to glucose in this population.

Hyperandrogenism sensitizes mononuclear cells to promote glucose-induced inflammation in lean reproductive-age women

Hyperandrogenism and chronic low-grade inflammation are related in polycystic ovary syndrome (PCOS), but it is unknown whether hyperandrogenemia can activate inflammation. We determined the effect of oral androgen administration on fasting and glucose-stimulated nuclear factor-κB (NF-κB) activation and expression and related markers of inflammation in mononuclear cells (MNC) of lean reproductive-age women. Sixteen lean, ovulatory reproductive-age women were treated with 130 mg of DHEA or placebo (n = 8 each) for 5 days in a randomized, controlled, double-blind fashion. Nuclear activation of NF-κB, p65 and p105 NF-κB subunit RNA, TNFα and IL-1β mRNA, and NF-κB p65 and inhibitory-κB (IκB) protein were quantified from MNC obtained while fasting and 2 h after glucose ingestion, before and after DHEA or placebo administration. Before treatment, subjects receiving DHEA or placebo exhibited no differences in androgens or any inflammatory markers while fasting and after glucose ingestion. Compared with placebo, DHEA administration raised levels of testosterone, androstenedione, and DHEA-S, increased the percent change in fasting and glucose-challenged activated NF-κB, p65, p105, TNFα, and IL-1β RNA and p65 protein, and decreased the percent change in fasting and glucose-challenged IκB protein. We conclude that elevation of circulating androgens to the range observed in PCOS upregulates the NF-κB inflammation pathway in lean reproductive-age women. Thus, hyperandrogenemia activates and sensitizes MNC to glucose in this population.

Alternative mechanism for anti-obesity effect of dehydroepiandrosterone: possible contribution of 11β-hydroxysteroid dehydrogenase type 1 inhibition in rodent adipose tissue

Dehydroepiandrosterone (DHEA) has been suggested to have an anti-obesity effect; however, the mechanism underlying this effect remains unclear. The effect of DHEA on adipocytes opposes that of glucocorticoids, which potentiate adipogenesis. The key to the intracellular activation of glucocorticoids in adipocytes is 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), which catalyses the production of active glucocorticoids (cortisol in humans and corticosterone in rodents) from an inactive 11-keto form (cortisone in humans and 11-dehydrocorticosterone in rodents). In humans and rodents, intracellular glucocorticoid reactivation is exaggerated in obese adipose tissue. Using differentiated 3T3-L1 adipocytes, we demonstrated that DHEA inhibited about 15.6% of 11β-HSD1 activity at a concentration of 1 μM within 10min. Inhibition was also observed in a cell-free system composed of microsomes prepared from rat adipose tissue and NADPH, a coenzyme of 11β-HSD1. A kinetic study revealed that DHEA acted as a non-competitive inhibitor of 11β-HSD1. Moreover, conversion from DHEA to estrogens was not observed by sensitive semi-micro HPLC equipped with electrochemical detector. These results indicate that the inhibition of 11β-HSD1 by DHEA depends on neither the transcriptional pathway nor the nonspecific manner. This is the first demonstration that the anti-obesity effect of DHEA is exerted by non-transcriptional inhibition of 11β-HSD1 in rodent adipocytes.

Genome-wide interaction-based association analysis identified multiple new susceptibility Loci for common diseases

Genome-wide interaction-based association (GWIBA) analysis has the potential to identify novel susceptibility loci. These interaction effects could be missed with the prevailing approaches in genome-wide association studies (GWAS). However, no convincing loci have been discovered exclusively from GWIBA methods, and the intensive computation involved is a major barrier for application. Here, we developed a fast, multi-thread/parallel program named "pair-wise interaction-based association mapping" (PIAM) for exhaustive two-locus searches. With this program, we performed a complete GWIBA analysis on seven diseases with stringent control for false positives, and we validated the results for three of these diseases. We identified one pair-wise interaction between a previously identified locus, C1orf106, and one new locus, TEC, that was specific for Crohn's disease, with a Bonferroni corrected P < 0.05 (P = 0.039). This interaction was replicated with a pair of proxy linked loci (P = 0.013) on an independent dataset. Five other interactions had corrected P < 0.5. We identified the allelic effect of a locus close to SLC7A13 for coronary artery disease. This was replicated with a linked locus on an independent dataset (P = 1.09 × 10⁻⁷). Through a local validation analysis that evaluated association signals, rather than locus-based associations, we found that several other regions showed association/interaction signals with nominal P < 0.05. In conclusion, this study demonstrated that the GWIBA approach was successful for identifying novel loci, and the results provide new insights into the genetic architecture of common diseases. In addition, our PIAM program was capable of handling very large GWAS datasets that are likely to be produced in the future.

Neurobiological and neuropsychiatric effects of dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS)

DHEA and DHEAS are steroids synthesized in human adrenals, but their function is unclear. In addition to adrenal synthesis, evidence also indicates that DHEA and DHEAS are synthesized in the brain, further suggesting a role of these hormones in brain function and development. Despite intensifying research into the biology of DHEA and DHEAS, many questions concerning their mechanisms of action and their potential involvement in neuropsychiatric illnesses remain unanswered. We review and distill the preclinical and clinical data on DHEA and DHEAS, focusing on (i) biological actions and putative mechanisms of action, (ii) differences in endogenous circulating concentrations in normal subjects and patients with neuropsychiatric diseases, and (iii) the therapeutic potential of DHEA in treating these conditions. Biological actions of DHEA and DHEAS include neuroprotection, neurite growth, and antagonistic effects on oxidants and glucocorticoids. Accumulating data suggest abnormal DHEA and/or DHEAS concentrations in several neuropsychiatric conditions. The evidence that DHEA and DHEAS may be fruitful targets for pharmacotherapy in some conditions is reviewed.

Could hormones make a difference in the treatment of juvenile rheumatoid arthritis?

Adrenal androgens dehydroepiandrosterone (DHEA; prasterone) and its sulphated form (DHEA-S) are among the most abundant hormonal steroids in men and nonpregnant women. Deficiencies of these adrenal androgens are associated with autoimmune disorders such as rheumatoid arthritis (RA). Recent studies from our laboratory have also identified low levels of adrenal androgens in the serum and synovial fluid of patients with juvenile rheumatoid arthritis (JRA). These findings support and complement those already published for RA and other autoimmune diseases. Because of the paucity of data on the hormonal status of patients with JRA, studies on the relationship between hypoandrogenicity and predisposition to develop JRA, and/or disease progression have not been conducted. In addition, despite the rapid expansion of research in the clinical use of these adrenal androgens in hyperlipidaemia, atherosclerosis, obesity, diabetes mellitus, insulin resistance and hypertension, their potential beneficial effects in JRA/RA have not been fully investigated. In fact, clinical trials of adrenal androgens in RA have only been conducted for the treatment of systemic lupus erythematosus. Further studies using prospective approaches are necessary to provide a unified consensus on the hormonal status of patients with JRA (as well as those with RA). This overview of our knowledge of the putative role(s) of hormones in arthritis will hopefully stimulate researchers in basic science and rheumatologists to synergistically collaborate in the effective translation of such knowledge to new clinical approaches.

DHEA induces 11 -HSD2 by acting on CCAAT/enhancer-binding proteins

11beta-Hydroxysteroid dehydrogenase (11beta-HSD) type 1 and type 2 catalyze the interconversion of inactive and active glucocorticoids. Impaired regulation of these enzymes has been associated with obesity, diabetes, hypertension, and cardiovascular disease. Previous studies in animals and humans suggested that dehydroepiandrosterone (DHEA) has antiglucocorticoid effects, but the underlying mechanisms are unknown. In this study, DHEA treatment markedly increased mRNA expression and activity of 11beta-HSD2 in a rat cortical collecting duct cell line and in kidneys of C57BL/6J mice and Sprague-Dawley rats. DHEA-treated rats tended to have reduced urinary corticosterone to 11-dehydrocorticosterone ratios. It was found that CCAAT/enhancer-binding protein-alpha (C/EBP-alpha) and C/EBP-beta regulated HSD11B2 transcription and that DHEA likely modulated the transcription of 11beta-HSD2 in a phosphatidylinositol-3 kinase/Akt-dependent manner by increasing C/EBP-beta mRNA and protein expression. Moreover, it is shown that C/EBP-alpha and C/EBP-beta differentially regulate the expression of 11beta-HSD1 and 11beta-HSD2. In conclusion, DHEA induces a shift from 11beta-HSD1 to 11beta-HSD2 expression, increasing conversion from active to inactive glucocorticoids. This provides a possible explanation for the antiglucocorticoid effects of DHEA.

Higher serum concentrations of DHEAS predict improved nutritional status in helminth-infected children, adolescents, and young adults in Leyte, the Philippines

Pubertal development and associated downmodulation of proinflammatory cytokines may predict improved nutritional status, independent of chronic parasite infections, in developing countries. We enrolled 731 individuals, aged 7-30 y, from Leyte, the Philippines, where helminth infections and nutritional morbidity are highly prevalent. The following data were collected: venous blood hemoglobin and serum concentrations of ferritin, dehydroepiandrosterone sulfate (DHEAS), C-reactive protein and proinflammatory cytokines (IL-1, IL-6, TNF-alpha, and soluble TNF receptor I); anthropometric measurements to calculate upper arm muscle area Z-score and sum of triceps and subscapular skinfolds Z-score; stool samples to determine Schistosoma japonicum and geohelminth egg counts; and responses to questionnaires assessing socio-economic status. In cross-sectional multilevel linear and logistic regression analyses adjusted for confounders, relations were assessed between 1) DHEAS and nutritional status, 2) DHEAS and proinflammatory cytokines, and 3) nutritional status and proinflammatory cytokines. Independent of age, socio-economic status, and helminth infections, increased levels of DHEAS were associated with improved nutritional status and decreased prevalence of non-iron deficiency anemia in both males and females. DHEAS showed dose-dependent inverse associations with C-reactive protein (P=0.08) and the production of IL-6 (P<0.0001). These inflammatory markers, in turn, were consistently associated with undernutrition and anemia. The results suggest that the puberty-associated rise in DHEAS downmodulates proinflammatory immune responses and thereby reduces undernutrition and anemia in a population experiencing a high burden of chronic helminth infections. This novel regulatory mechanism of inflammation-related nutritional morbidity emphasizes the importance of treating prepubescent children for helminth infections.

Dehydroepiandrosterone increases β-cell mass and improves the glucose-induced insulin secretion by pancreatic islets from aged rats

The effect of dehydroepiandrosterone (DHEA) on pancreatic islet function of aged rats, an animal model with impaired glucose-induced insulin secretion, was investigated. The following parameters were examined: morphological analysis of endocrine pancreata by immunohistochemistry; protein levels of insulin receptor, IRS-1, IRS-2, PI 3-kinase, Akt-1, and Akt-2; and static insulin secretion in isolated pancreatic islets. Pancreatic islets from DHEA-treated rats showed an increased beta-cell mass accompanied by increased Akt-1 protein level but reduced IR, IRS-1, and IRS-2 protein levels and enhanced glucose-stimulated insulin secretion. The present results suggest that DHEA may be a promising drug to prevent diabetes during aging.

Effect of DHEA on endocrine functions of adipose tissue, the involvement of PPAR gamma

Dehydroepiandrosterone (DHEA), an adrenal steroid, is known to decrease body fat. Thus, it may also alter the endocrine functions of adipose tissue. The aim of this study was to determine if administration of DHEA might influence adiponectin gene expression and secretion from adipose tissue. We demonstrate here the inducing effect of exogenously administered DHEA on adiponectin gene expression in epididymal WAT and adiponectin levels in serum of rats fed a DHEA-containing diet (0.6%, w/w) for 2 weeks, accompanied by a reduction in epididymal adipose tissue mass. A corresponding increase in peroxisome proliferator-activated receptor gamma (PPAR(gamma)) mRNA expression suggests that PPAR(gamma) may be involved in the up-regulation of adiponectin gene expression after DHEA treatment. The presented observations indicate that the positive effects of DHEA, which seems to play a protective role against insulin resistance and atherosclerosis, may be in fact indirect and due to up-regulation of adiponectin gene expression and stimulation of adiponectin secretion from adipose tissue.

Insulin-sensitising agents: beyond thiazolidinediones

The global prevalence of Type 2 diabetes mellitus is increasing rapidly, at least in part as a function of obesity. The results of the United Kingdom Prospective Diabetes Study emphasise the importance of developing safe, efficacious new agents for the treatment of Type 2 diabetes. The pharmaceutical industry has recently focused on strategies to improve insulin resistance, particularly modulation of PPAR-gamma. Here we review current thinking on the mechanism of action of these agents, and consider future directions that may arise as a result of increasing understanding of the biology of these receptors and of insulin action. Studies of thiazolidinedione action in adipose tissue have revealed several novel adipocyte-derived hormones that may also be future pharmacological targets for increasing insulin sensitivity. The role of other hormones, such as cortisol and dehydroepiandrosterone, are also discussed in a therapeutic context, as are other novel approaches to the pharmacological management of patients with insulin resistance and Type 2 diabetes.

Association between urinary albumin excretion and serum dehydroepiandrosterone sulfate concentration in male patients with type 2 diabetes: a possible link between urinary albumin excretion and cardiovascular disease

OBJECTIVE

Cardiovascular disease (CVD) is the leading cause of mortality and morbidity in patients with type 2 diabetes. Both elevated urinary albumin excretion and low serum concentrations of dehydroepiandrosterone (DHEA) are associated with increased CVD mortality. This raises the possibility of DHEA as a causal intermediate linking urinary albumin excretion to CVD.

RESEARCH DESIGN AND METHODS

Relationships of urinary albumin excretion to serum DHEA sulfate (DHEA-S) concentration and to major cardiovascular risk factors, including blood pressure, serum lipid concentration, glycemic control (HbA1c), and BMI, were investigated in 357 consecutive men with type 2 diabetes.

RESULTS

Serum DHEA-S concentrations were lower in patients with macroalbuminuria (866.5 +/- 523.8 ng/ml, P <0.0001) and in those with microalbuminuria (1,014.4 +/- 525.3 ng/ml, P=0.0006) than in patients with normoalbuminuria (1,232.6 +/- 542.4 ng/ml). Serum DHEA-S concentration correlated inversely with log (urinary albumin excretion) (r=-0.227, P <0.0001). Multiple regression analysis demonstrated that duration of diabetes (beta=0.147, P=0.0075), HbA1c (beta=0.156, P=0.0048), BMI (beta=0.194, P=0.0007), systolic blood pressure (beta=0.195, P=0.0005), and serum DHEA-S concentration (beta=-0.192, P=0.0010) were independent determinants of log (urinary albumin excretion).

CONCLUSIONS

Serum DHEA-S concentration, which correlated inversely with degree of urinary albumin excretion, may contribute to the link between elevated urinary albumin excretion and higher CVD mortality in male patients with type 2 diabetes.

Skeletal muscle contraction stimulates capillary recruitment and glucose uptake in insulin-resistant obese Zucker rats

Exercise and insulin increase muscle glucose uptake by different mechanisms and also increase capillary recruitment, which is proposed to facilitate access for hormones and nutrients. The genetically obese Zucker rat shows impaired insulin- but not contraction-mediated glucose uptake in muscle. Recently, we have shown the genetically obese Zucker rats to have impaired insulin-mediated capillary recruitment and proposed that this contributes to the insulin resistance of muscle in vivo. Because this might imply a general loss of recruitable capillaries, we now assess responses to contraction in muscles of 18 +/- 3-wk-old lean and obese Zucker rats in vivo. Field stimulation (2 Hz, 0.1 ms) was conducted for 1 h on one leg of anesthetized instrumented rats, and measurements were made of femoral blood flow (FBF), heart rate (HR), blood pressure (BP), hindleg metabolism of 1-methylxanthine (a measure of capillary recruitment), hindleg glucose uptake (HGU), and lower leg muscle glucose uptake by 2-deoxyglucose (R'g). Lean animals (311 +/- 9 g) developed tension at 219 +/- 27 g/g muscle with no change in BP but with significant increases in HR, FBF, HGU, 1-MX metabolism, and R'g (P < 0.05), compared with nonstimulated control leans. Obese animals (469 +/- 7 g) developed tension at 265 +/- 31 g/g muscle with no change in HR or BP but with significant increases in FBF, HGU, 1-MX metabolism, and R'g (P < 0.05) compared with nonstimulated control obese rats. Muscle contraction of lean animals led to a greater increase in lower leg R'g, similar responses in HGU and 1-MX, and a smaller increase in FBF than in obese animals. A tight correlation between FBF and capillary recruitment was noted for all data (P < 0.001). It is concluded that contraction-mediated muscle capillary recruitment and glucose uptake are essentially normal in the obese Zucker rat and that control of FBF and capillary recruitment in exercise is closely linked.

Dehydroepiandrosterone decreases elevated hepatic glucose production in C57BL/KsJ-db/db mice

Dehydroepiandrosterone (DHEA) is known to improve hyperglycemia in diabetic db/db mice that are obese and insulin resistant. In a previous study, we reported that DHEA suppresses the elevated hepatic gluconeogenic glucose-6-phosphatase (G6Pase) activity and gene expression in C57BL/KsJ-db/db mice. In the present study, we evaluated the total amount of gluconeogenesis using NaH[(14)C]CO(3) and hepatic glucose production using fructose as a substrate in primary cultured hepatocytes. Despite hyperinsulinemia, the glucose production of db/db mice in the total body and hepatocytes was elevated as compared to their heterozygote littermate C57BL/KsJ-db/+m mice. Administration of DHEA significantly decreased the blood glucose level and increased the plasma insulin level in db/db mice. Administration of DHEA decreased the elevated total body and hepatic glucose production in db/db mice. In addition, the glucose production in the primary cultured hepatocytes of db/db mice was decreased significantly by the direct addition of DHEA or DHEA-S to the medium. These results suggest that administration of DHEA suppresses the elevated total body and hepatic glucose production in db/db mice, and this effect on the liver is considered to result from increased plasma insulin and DHEA or DHEA-S itself.

Cœur et androgènes

Beyond regulation of sexual function, male steroids play an important role in many physiological homeostasis systems, including the cardiovascular system. Via a specific androgen receptor, testosterone mediates cardiomyocyte trophicity both in physiological situations and in hypertrophy-related cardiac diseases. Androgens also regulate pathological levels of inflammatory cytokines such as Il-6 or TNF in advanced heart failure. They also mediate vascular resistance since coronary vasodilatation has been proven both in vitro and in vivo. Reduced free testosterone serum levels (age-mediated or premature coronary artery disease) promote a pro-atherogenic lipid profile expressed as lower serum HDL-cholesterol and up-regulation of triglyceride levels. This observation has relevant clinical implications for the evaluation and treatment of coronary artery disease. As most of normal and diseased cardiovascular system functions are influenced by androgens, further evaluation of their physiological implications should be undertaken as well as large-scale rigorous studies of the therapeutic implications in two disabling diseases, coronary heart disease and heart failure.

Dehydroepiandrosterone stimulates glucose uptake in human and murine adipocytes by inducing GLUT1 and GLUT4 translocation to the plasma membrane

Dehydroepiandrosterone (DHEA) has been shown to modulate glucose utilization in humans and animals, but the mechanisms of DHEA action have not been clarified. We show that DHEA induces a dose- and time-dependent increase in glucose transport rates in both 3T3-L1 and human adipocytes with maximal effects at 2 h. Exposure of adipocytes to DHEA does not result in changes of total GLUT4 and GLUT1 protein levels. However, it does result in significant increases of these glucose transporters in the plasma membrane. In 3T3-L1 adipocytes, DHEA increases tyrosine phosphorylation of insulin receptor substrate (IRS)-1 and IRS-2 and stimulates IRS-1- and IRS-2-associated phosphatidylinositol (PI) 3-kinase activity with no effects on either insulin receptor or Akt phosphorylation. In addition, DHEA causes significant increases of cytosolic Ca(2+) concentrations and a parallel activation of protein kinase C (PKC)-beta(2). The effects of DHEA are abrogated by pretreatment of adipocytes with PI 3-kinase and phospholipase C gamma inhibitors, as well as by inhibitors of Ca(2+)-dependent PKC isoforms, including a specific PKC-beta inhibitor. Thus, DHEA increases glucose uptake in both human and 3T3-L1 adipocytes by stimulating GLUT4 and GLUT1 translocation to the plasma membrane. PI 3-kinase, phospholipase C gamma, and the conventional PKC-beta(2) seem to be involved in DHEA effects.

Prevention of diabetes, hepatic injury, and colon cancer with dehydroepiandrosterone

The levels of dehydroepiandrosterone (DHEA) and its sulfate (DHEA-S) peak in human in their twenties, then decrease gradually with age. The physiological importance of DHEA was not clear until recent research reports showing that DHEA has beneficial effects on preventing diabetes, malignancy, inflammation, osteoporosis, and collagen disease. We summarize our results concerning diabetes, hepatitis, and colon cancer. In 1982, Coleman et al. [Diabetes 31 (1982) 830] reported that DHEA decreased hyperglycemia in diabetic db/db mice, which become insulin resistant. We measured hepatic gluconeogenic enzymes in an attempt to elucidate the mechanical mechanism of DHEA action. The activity and gene expression of hepatic gluconeogenic enzyme such as glucose-6-phosphatase (G6Pase) was increased in db/db mice despite hyperinsulinemia compared to control db/+m mice. DHEA, like troglitazone, decreased these levels in db/db mice. We also showed that DHEA improved the insulin resistance caused by aging or obesity using the glucose clamp technique in another animal model. In humans, the serum DHEA concentration was shown to be associated with hyperinsulinemia in diabetes. It also became clear that DHEA increased insulin secretion in old-aged db/db mice. DHEA increases not only insulin sensitivity due to the effects in the liver and muscle, but also insulin secretion. As an effect of DHEA on T-cell mediated hepatitis induced by concanavalin A (ConA), DHEA reduced hepatic injury by inhibiting several inflammatory mediators and apoptosis. As an effect of DHEA on carcinogenesis, DHEA would be a potential chemopreventative agent against colon cancer because it decreases the number of azoxymethane (AOM) induced aberrant crypt foci, which is a possible precursor to adenoma and cancer in a murine model.Thus, since DHEA has many beneficial effects experimentally, we should consider administration of DHEA in the future, and common mechanisms among these actions of DHEA should be elucidated in further studies.

Androgens and coronary artery disease

A significant and independent association between endogenous testosterone (T) levels and coronary events in men and women has not been confirmed in large prospective studies, although cross-sectional data have suggested coronary heart disease can be associated with low T in men. Hypoandrogenemia in men and hyperandrogenemia in women are associated with visceral obesity; insulin resistance; low high-density lipoprotein (HDL) cholesterol (HDL-C); and elevated triglycerides, low-density lipoprotein cholesterol, and plasminogen activator type 1. These gender differences and confounders render the precise role of endogenous T in atherosclerosis unclear. Observational studies do not support the hypothesis that dehydroepiandrosterone sulfate deficiency is a risk factor for coronary artery disease. The effects of exogenous T on cardiovascular mortality or morbidity have not been extensively investigated in prospective controlled studies; preliminary data suggest there may be short-term improvements in electrocardiographic changes in men with coronary artery disease. In the majority of animal experiments, exogenous T exerts either neutral or beneficial effects on the development of atherosclerosis. Exogenous androgens induce both apparently beneficial and deleterious effects on cardiovascular risk factors by decreasing serum levels of HDL-C, plasminogen activator type 1 (apparently deleterious), lipoprotein (a), fibrinogen, insulin, leptin, and visceral fat mass (apparently beneficial) in men as well as women. However, androgen-induced declines in circulating HDL-C should not automatically be assumed to be proatherogenic, because these declines may instead reflect accelerated reverse cholesterol transport. Supraphysiological concentrations of T stimulate vasorelaxation; but at physiological concentrations, beneficial, neutral, and detrimental effects on vascular reactivity have been observed. T exerts proatherogenic effects on macrophage function by facilitating the uptake of modified lipoproteins and an antiatherogenic effect by stimulating efflux of cellular cholesterol to HDL. In conclusion, the inconsistent data, which can only be partly explained by differences in dose and source of androgens, militate against a meaningful assessment of the net effect of T on atherosclerosis. Based on current evidence, the therapeutic use of T in men need not be restricted by concerns regarding cardiovascular side effects. Available data also do not justify the uncontrolled use of T or dehydroepiandrosterone for the prevention or treatment of coronary heart disease.

Seasonal adiposity and delayed ovulation in a vespertilionid bat, Scotophilus heathi: role of tumor necrosis factor-alpha

The aim of this article was to evaluate the physiological significance of tumor necrosis factor-alpha (TNF-alpha) in seasonal accumulation of adipose tissue, hyperinsulinemia, and anovulation in Scotophilus heathi. The result showed seasonal variations in the circulating TNF-alpha level. A higher level of circulating TNF-alpha was observed during quiescence and recrudescence, whereas a lower level of TNF-alpha was observed during winter dormancy and the preovulatory period. An increased circulating TNF-alpha level coincided closely with accumulation of adipose tissue and hyperinsulinemia. Immunocytochemical localization of TNF-alpha in the ovary showed immunoreactivity mainly in the oocytes and theca-interstitial cells. The oocytes of small and medium-sized follicles showed strong TNF-alpha immunostaining, whereas weak immunoreactivity was observed in the large antral follicles. The atretic follicles showed mild TNF-alpha immunostaining. TNF-alpha immunoreactivity in the ovary was slightly higher during the quiescence and preovulatory periods compared with the periods of recrudescence and winter dormancy. TNF-alpha alone significantly increased androstenedione and estradiol production by the ovary in vitro but did not augment the luteinizing hormone (LH)-induced androstenedione production. However, TNF-alpha did augment LH-induced estradiol production. The results of this study suggest the involvement of TNF-alpha in the interaction among adipose tissue accumulation, insulin resistance, and ovarian activity in S. heathi.

Dehydroepiandrosterone down-regulates the expression of peroxisome proliferator-activated receptor gamma in adipocytes

Dehydroepiandrosterone (DHEA) is expected to have a weight-reducing effect. In this study, we evaluated the effect of DHEA on genetically obese Otsuka Long Evans Fatty rats (OLETF) compared with Long-Evans Tokushima rats (LETO) as control. Feeding with 0.4% DHEA-containing food for 2 wk reduced the weight of sc, epididymal, and perirenal adipose tissue in association with decreased plasma leptin levels in OLETF. Adipose tissue from OLETF showed increased expression of peroxisome proliferator-activated receptor gamma (PPARgamma) protein, which was prevented by DHEA treatment. Further, we examined the effect of DHEA on PPARgamma in primary cultured adipocytes and monolayer adipocytes differentiated from rat preadipocytes. PPARgamma protein level was decreased in a time- and concentration-dependent manner, and DHEA significantly reduced mRNA levels of PPARgamma, adipocyte lipid-binding protein, and sterol regulatory element-binding protein, but not CCAAT/enhancer binding protein alpha. DHEA-sulfate also reduced the PPARgamma protein, but dexamethasone, testosterone, or androstenedione did not alter its expression. In addition, treatment with DHEA for 5 d reduced the triglyceride content in monolayer adipocytes. These results suggest that DHEA down-regulates adiposity through the reduction of PPARgamma in adipocytes.

Heart failure as an inflammatory condition: potential role for androgens as immune modulators

Heart failure has traditionally been considered a disease of the myocardium, with symptoms arising from altered haemodynamics. However, it is now recognised that, in addition to marked neuroendocrine disturbance, there is perturbation of cytokine expression in patients with heart failure, resulting in an inflammatory imbalance. This not only influences symptoms, but also plays a central role in the underlying pathophysiological processes of heart failure, leading to disease progression and poorer prognosis. Recognition of the influence of cytokines, in particular tumour necrosis factor, has opened a new avenue for potential therapies for heart failure. Current approaches involve immunomodulation, aimed at suppressing tumour necrosis factor. We suggest that androgens may potentially offer a superior therapeutic strategy by their well-recognised non-specific immunosuppressive and anti-inflammatory effects. Studies of cell lines, human mononuclear cells and animals in vivo have demonstrated the 'anti-cytokine' actions of androgens, and we have found a similar action in whole blood from patients with heart failure. These effects, along with the anabolic action of these agents, make androgens an attractive potential option for treatment of patients with heart failure.

Insulin-mediated hemodynamic changes are impaired in muscle of Zucker obese rats

Insulin-mediated hemodynamic effects in muscle were assessed in relation to insulin resistance in obese and lean Zucker rats. Whole-body glucose infusion rate (GIR), femoral blood flow (FBF), hindleg glucose extraction (HGE), hindleg glucose uptake (HGU), 2-deoxyglucose (DG) uptake into muscles of the lower leg (R(g)), and metabolism of infused 1-methylxanthine (1-MX) to measure capillary recruitment were determined for isogylcemic (4.8 +/- 0.2 mmol/l, lean; 11.7 +/- 0.6 mmol/l, obese) insulin-clamped (20 mU. min(-1). kg(-1) x 2 h) and saline-infused control anesthetized age-matched (20 weeks) lean and obese animals. Obese rats (445 +/- 5 g) were less responsive to insulin than lean animals (322 +/- 4 g) for GIR (7.7 +/- 1.4 vs. 22.2 +/- 1.1 mg. min(-1). kg(-1), respectively), and when compared with saline-infused controls there was no increase due to insulin by obese rats in FBF, HGE, HGU, and R(g) of soleus, plantaris, red gastrocnemius, white gastrocnemius, extensor digitorum longus (EDL), or tibialis muscles. In contrast, lean animals showed marked increases due to insulin in FBF (5.3-fold), HGE (5-fold), HGU (8-fold), and R(g) ( approximately 5.6-fold). Basal (saline) hindleg 1-MX metabolism was 1.5-fold higher in lean than in obese Zucker rats, and insulin increased in only that of the lean. Hindleg 1-MX metabolism in the obese decreased slightly in response to insulin, thus postinsulin lean was 2.6-fold that of the postinsulin obese. We conclude that muscle insulin resistance of obese Zucker rats is accompanied by impaired hemodynamic responses to insulin, including capillary recruitment and FBF.

Radioprotective efficacy and acute toxicity of 5-androstenediol after subcutaneous or oral administration in mice

We previously showed that one subcutaneous (sc) injection of 5-androstene-3beta,17beta-diol (AED) stimulated the innate immune system in mice and prevented mortality due to hemopoietic suppression after whole-body ionizing irradiation with gamma rays. In the present study, we tested whether there was any significant toxicity in mice that might hinder development of this steroid for human use. There were no indications of toxicity in chemical analyses of serum after sc doses as high as 4000 mg/kg. At this dose, 2 of 54 mice died when given AED alone. When 4800 mg/kg was given orally, no deaths resulted. The only adverse findings attributed to AED administration were 1) a moderate elevation of granulocytes in abdominal organs and fat after sc injections of 320 mg/kg; and 2) occasional wasting of skin over the injection site in female B6D2F1 but not male C3H/HeN mice. Significant weight loss (6%) was observed after sc injections of 320 mg/kg but not 160 or 80 mg/kg. When male C3H/HeN mice were injected sc with AED at doses of 0-200 mg/kg 24 h before whole body gamma-irradiation (9 Gy), a significant improvement in survival was observed at doses as low as 5 mg/kg. Oral administration of AED produced significant survival enhancement at a dose of 1600 mg/kg. We conclude that the radioprotective efficacy of AED is accompanied by low toxicity.

Effects of prasterone on corticosteroid requirements of women with systemic lupus erythematosus: a double-blind, randomized, placebo-controlled trial

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.

CONCLUSION

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.

Changes in proinflammatory cytokine activity after menopause

There is now a large body of evidence suggesting that the decline in ovarian function with menopause is associated with spontaneous increases in proinflammatory cytokines. The cytokines that have obtained the most attention are IL-1, IL-6, and TNF-alpha. The exact mechanisms by which estrogen interferes with cytokine activity are still incompletely known but may potentially include interactions of the ER with other transcription factors, modulation of nitric oxide activity, antioxidative effects, plasma membrane actions, and changes in immune cell function. Experimental and clinical studies strongly support a link between the increased state of proinflammatory cytokine activity and postmenopausal bone loss. Preliminary evidence suggests that these changes also might be relevant to vascular homeostasis and the development of atherosclerosis. Better knowledge of the mechanisms and the time course of these interactions may open new avenues for the prevention and treatment of some of the most prevalent and important disorders in postmenopausal women.

The adrenal and the metabolic syndrome

This review discusses the possible interrelationships between adrenal steroid hormones and the metabolic syndrome. Abnormal regulation of the hypothalamic-pituitary-adrenal axis has been proposed. Studies in the United Kingdom associated the metabolic syndrome with low birth weight and hyperactivity of the entire axis. In Italy, increased pituitary responsiveness to stimulation with vasopressin and corticotrophin-releasing hormone was demonstrated in women with central obesity. Swedish researchers have reported that increased stress responses of the axis correlated with a less variable but decreased cortisol level. An allele of the glucocorticoid receptor was also associated with various components of the metabolic syndrome. Evidence also suggests that central obesity is associated with an increased peripheral conversion of cortisol to cortisone and subsequent feedback stimulation of the axis. On the other hand, central fat may have an increased local metabolism in the direction of cortisol. Roles for dehydroepiandrosterone and aldosterone in the syndrome have also been proposed.

Effects of clenbuterol on insulin resistance in conscious obese Zucker rats

The present study was conducted to determine the effect of chronic administration of the long-acting beta(2)-adrenergic agonist clenbuterol on rats that are genetically prone to insulin resistance and impaired glucose tolerance. Obese Zucker rats (fa/fa) were given 1 mg/kg of clenbuterol by oral intubation daily for 5 wk. Controls received an equivalent volume of water according to the same schedule. At the end of the treatment, rats were catheterized for euglycemic-hyperinsulinemic (15 mU insulin. kg(-1). min(-1)) clamping. Clenbuterol did not change body weight compared with the control group but caused a redistribution of body weight: leg muscle weights increased, and abdominal fat weight decreased. The glucose infusion rate needed to maintain euglycemia and the rate of glucose disappearance were greater in the clenbuterol-treated rats. Furthermore, plasma insulin levels were decreased, and the rate of glucose uptake into hindlimb muscles and abdominal fat was increased in the clenbuterol-treated rats. This increased rate of glucose uptake was accompanied by a parallel increase in the rate of glycogen synthesis. The increase in muscle glucose uptake could not be ascribed to an increase in the glucose transport protein GLUT-4 in clenbuterol-treated rats. We conclude that chronic clenbuterol treatment reduces the insulin resistance of the obese Zucker rat by increasing insulin-stimulated muscle and adipose tissue glucose uptake. The improvements noted may be related to the repartitioning of body weight between tissues.