Is there a case for DHEA replacement?

The Immunoregulatory Actions of DHEA in Tuberculosis, A Tool for Therapeutic Intervention?

Dehydroepiandrosterone (DHEA) is an androgen synthesized by the adrenal cortex, which is an intermediary in the biosynthesis of sex hormones, such as testosterone and estradiol. DHEA mostly circulates as a conjugated ester, in the form of sulfate (DHEA-S). There exist several endogenous factors able to influence its synthesis, the most common ones being the corticotrophin-releasing hormone (CRH), adrenocorticotrophin (ACTH), growth factors, and proinflammatory cytokines, among others. Like other steroid hormones, DHEA, can alter the functioning of immune cells and therefore the course of diseases exhibiting an immune-inflammatory component, mostly from autoimmune or infectious nature. We herein review the role played by DHEA during a major infectious disease like tuberculosis (TB). Data recorded from TB patients, mouse models, or in vitro studies show that DHEA is likely to be implied in better disease control. This provides a stimulating background for carrying out clinical studies aimed at assessing the usefulness of DHEA as an adjuvant in TB patients.

Effect of Dehydroepiandrosterone and Testosterone Supplementation on Systemic Lipolysis

CONTEXT

Dehydroepiandrosterone (DHEA) and T hormones are advertised as antiaging, antiobesity products. However, the evidence that these hormones have beneficial effects on adipose tissue metabolism is limited.

OBJECTIVE

The objective of the study was to determine the effect of DHEA and T supplementation on systemic lipolysis during a mixed-meal tolerance test (MMTT) and an iv glucose tolerance test (IVGTT).

DESIGN

This was a 2-year randomized, double-blind, placebo-controlled trial.

SETTING

The study was conducted at a general clinical research center.

PARTICIPANTS

Sixty elderly women with low DHEA concentrations and 92 elderly men with low DHEA and bioavailable T concentrations participated in the study.

INTERVENTIONS

Elderly women received 50 mg DHEA (n = 30) or placebo (n = 30). Elderly men received 75 mg DHEA (n = 30), 5 mg T (n = 30), or placebo (n = 32).

MAIN OUTCOME MEASURES

In vivo measures of systemic lipolysis (palmitate rate of appearance) during a MMTT or IVGTT.

RESULTS

At baseline there was no difference in insulin suppression of lipolysis measured during MMTT and IVGTT between the treatment groups and placebo. For both sexes, a univariate analysis showed no difference in changes in systemic lipolysis during the MMTT or IVGTT in the DHEA group and T group when compared with placebo. There was no change in the results after adjusting for the resting energy expenditure, except for a small, but significant (P = .03) lowering of MMTT nadir palmitate rate of appearance in women who received DHEA.

CONCLUSION

In elderly individuals with concentrations of DHEA (men and women) or T (men) below the normal range for young adults, supplementation of these hormones has no effect on insulin suppression of systemic lipolysis.

Genetics of androgen metabolism in women with infertility and hypoandrogenism

Hypoandrogenism in women with low functional ovarian reserve (LFOR, defined as an abnormally low number of small growing follicles) adversely affects fertility. The androgen precursor dehydroepiandrosterone (DHEA) is increasingly used to supplement treatment protocols in women with LFOR undergoing in vitro fertilization. Due to differences in androgen metabolism, however, responses to DHEA supplementation vary between patients. In addition to overall declines in steroidogenic capacity with advancing age, genetic factors, which result in altered expression or enzymatic function of key steroidogenic proteins or their upstream regulators, might further exacerbate variations in the conversion of DHEA to testosterone. In this Review, we discuss in vitro studies and animal models of polymorphisms and gene mutations that affect the conversion of DHEA to testosterone and attempt to elucidate how these variations affect female hormone profiles. We also discuss treatment options that modulate levels of testosterone by targeting the expression of steroidogenic genes. Common variants in genes encoding DHEA sulphotransferase, aromatase, steroid 5α-reductase, androgen receptor, sex-hormone binding globulin, fragile X mental retardation protein and breast cancer type 1 susceptibility protein have been implicated in androgen metabolism and, therefore, can affect levels of androgens in women. Short of screening for all potential genetic variants, hormonal assessments of patients with low testosterone levels after DHEA supplementation facilitate identification of underlying genetic defects. The genetic predisposition of patients can then be used to design individualized fertility treatments.

Clinical biochemistry of dihydrotestosterone

Dihydrotestosterone (DHT) is the most potent natural androgen in humans. There has been an increasing interest in this androgen and its role in the development of primary and secondary sexual characteristics as well as its potential roles in diseases ranging from prostate and breast cancer to Alzheimer's disease. Despite the range of pathologies shown to involve DHT there is little evidence for measurement of serum DHT in the management of these diseases. In this review we describe the physiology of DHT production and action, summarize current concepts in the role of DHT in the pathogenesis of various disorders of sexual development, compare current methods for the measurement of DHT and conclude on the clinical utility of DHT measurement. The clinical indications for the measurement of DHT in serum are: investigation of 5α reductase deficiency in infants with ambiguous genitalia and palpable gonads; men with delayed puberty and/or undescended testes; and to confirm the presence of active testicular tissue. Investigation is aided by the use of human chorionic gonadotrophin stimulation. Due to paucity of published data on this procedure, it is important to follow guidelines prescribed by the laboratory performing the analysis to ensure accurate interpretation.

Hormonal causes of male sexual dysfunctions and their management (hyperprolactinemia, thyroid disorders, GH disorders, and DHEA)

INTRODUCTION

Besides hypogonadism, other endocrine disorders have been associated with male sexual dysfunction (MSD).

AIM

To review the role of the pituitary hormone prolactin (PRL), growth hormone (GH), thyroid hormones, and adrenal androgens in MSD.

METHODS

A systematic search of published evidence was performed using Medline (1969 to September 2011). Oxford Centre for Evidence-Based Medicine-Levels of Evidence (March 2009) was applied when possible.

MAIN OUTCOME MEASURES

The most important evidence regarding the role played by PRL, GH, thyroid, and adrenal hormone was reviewed and discussed.

RESULTS

Only severe hyperprolactinemia (>35 ng/mL or 735 mU/L), often related to a pituitary tumor, has a negative impact on sexual function, impairing sexual desire, testosterone production, and, through the latter, erectile function due to a dual effect: mass effect and PRL-induced suppression on gonadotropin secretion. The latter is PRL-level dependent. Emerging evidence indicates that hyperthyroidism is associated with an increased risk of premature ejaculation and might also be associated with erectile dysfunction (ED), whereas hypothyroidism mainly affects sexual desire and impairs the ejaculatory reflex. However, the real incidence of thyroid dysfunction in subjects with sexual problems needs to be evaluated. Prevalence of ED and decreased libido increase in acromegalic patients; however, it is still a matter of debate whether GH excess (acromegaly) may create effects due to a direct overproduction of GH/insulin-like growth factor 1 or because of the pituitary mass effects on gonadotropic cells, resulting in hypogonadism. Finally, although dehydroepiandrosterone (DHEA) and its sulfate have been implicated in a broad range of biological derangements, controlled trials have shown that DHEA administration is not useful for improving male sexual function.

CONCLUSIONS

While the association between hyperprolactinemia and hypoactive sexual desire is well defined, more studies are needed to completely understand the role of other hormones in regulating male sexual functioning.

Enhancement of Cognitive and Electrophysiological Measures of Hippocampal Functioning in Rats by a Low, But Not High, Dose of Dehydroepiandrosterone Sulfate (DHEAS)

Dehydroepiandrosterone sulfate (DHEAS) is a steroid hornone that is synthesized, de novo, in the brain. Endogenous DHEAS levels correlate with the quality of mental and physical health, where the highest levels of DHEAS occur in healthy young adults and reduced levels of DHEAS are found with advanced age, disease, or extreme stress. DHEAS supplementation, therefore, may serve as a therapeutic agent against a broad range of maladies. This paper summarizes laboratory findings on dose-response relationships between DHEAS and cognitive and electrophysiological measures of hippocampal functioning. It was found that a low, but not a high, dose of DHEAS enhanced hippocampal primed burst potentiation (a physiological model of memory) as well as spatial (hippocampal-dependent) memory in rats. This complex dose-response function of DHEAS effects on the brain and memory may contribute toward the inconsistent findings that have been obtained by other investigators in studies on DHEAS administration in people.

Effects of the chronic use of dehydroepiandrosterone (DHEA) on testicular weight and spermatogenesis: experimental study in rats

AIM

The complete biological effects of chronic use of dehydroepiandrosterone (DHEA), reported as a weak androgen, are not completely understood. The aim of the present study is to evaluate the effects of chronic administration of DHEA on the spermatogenesis in rats.

METHODS

Male Wistar rats, 4 months old, were selected for the study. The animals were divided into two groups. Group 1 (n = 9) received placebo (saline solution) 0.5 ml/day and Group 2 (n = 15) received DHEA 5 mg/kg/day. Both the groups received the respective treatments 5 days a week during 10 months. At the end of the exposure, the rats were sacrificed and the testes removed, weighed and processed for histologic analysis. Spermatogenesis was evaluated as the mean number of seminiferous tubules with and without spermatids in maturation phase in their lumen, in five random fields on the same slide.

RESULTS

The median levels of serum total testosterone and dehydroepiandrosterone sulfate was measured in the two groups. Significant higher concentrations in total testosterone (2.06 +/- 0.4 vs. 0.80 +/- 0.2; p < 0.05) and DHEAS (222.1 +/- 41.5 vs. 2.0 +/- 0.3) were observed in the group treated with DHEA as compared to the control group. The mean weights of the right testes were 1.59 +/- 0.3 in group 1 and 1.58 +/- 0.2 g in group 2 (p > 0.05). These values for the left testes were 1.57 +/- 0.3 and 1.55 +/- 0.3 g, respectively (p > 0.05). The histologic analysis showed a mean of 13.5 +/- 1.5 and 12.8 +/- 1.8 seminiferous tubules per field in the groups 1 and 2, respectively (p > 0.05). The same analysis demonstrated that in the control group 0.06 +/- 0.1 of the tubules presented without spermatids in maturation phase and in the DHEA group this was observed in 0.22 +/- 1.2 of the tubules (p > 0.05).

CONCLUSION

Chronic administration of DHEA in the present dose did not show any detectable effect on the quantitative and qualitative analyses of spermatogenesis in rats.

Effects of Chronic Administration of Dehydroepiandrosterone on Serum Testosterone Levels and Prostatic Tissue in Rats

PURPOSE

We evaluated the effects of chronic administration of dehydroepiandrosterone (DHEA) on serum total testosterone and DHEA sulfate (DHEAS), prostatic weight and histological features in the rat.

MATERIALS AND METHODS

Wistar rats were divided into 2 groups. The first group of 9 rats received saline solution orally once daily during 5 days of the week for 10 months and the second group of 15 received 5 mg/kg daily DHEA in suspension orally in the same pattern.

RESULTS

At the end of the 10-month study period total testosterone levels were higher in the DHEA group compared with controls (2.0 +/- 0.4 vs 0.8 +/- 0.2 mg/dl, p <0.0001) and DHEAS levels were also greater in the treated group compared with placebo (222.1 +/- 41.5 vs 2.0 +/- 0.3 mg/dl, p <0.0001). Weight of the prostate, testis and body did not differ between the groups (p >0.05). No differences between the 2 groups were noted in regard to the degree of hyperplasia, atrophy, a papillary component or the stromal-to-gland ratio (p >0.05).

CONCLUSIONS

Oral ingestion of DHEA on a chronic basis in the rat increases serum DHEAS and total testosterone without any evident change in prostate weight or histology.

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.

Sex differences in androgen receptor immunoreactivity in basal forebrain nuclei of elderly and Alzheimer patients

The vertical limb of the diagonal band of Broca (VDB or Ch2) and the nucleus basalis of Meynert (NBM or Ch4) are major cholinergic nuclei of the human basal forebrain, a complex that is affected in Alzheimer's disease (AD). Sex hormones influence the function of these cholinergic neurons in animals and humans and we showed earlier that estrogen and androgen receptors (AR) are present in both the VDB and the NBM of young patients of 20-39 years of age. The aim of the present study was to investigate whether AR expression changes in relation to aging and AD. In both brain areas of male and female patients over the age of 56 nuclear staining had almost disappeared and cytoplasmic AR expression was decreased. This decrease was most pronounced in the VDB of men. In addition, the proportion of neurons showing cytoplasmic AR expression was higher in control aged women than in control aged men in both the VDB and the NBM. Surprisingly, cytoplasmic ARs were significantly decreased in the VDB and the NBM only in AD women and not in AD men. These observations suggest the possible involvement of androgens in the functional changes of the basal forebrain nuclei in aging and AD.

DHEA and sport

Dehydroepiandrosterone (DHEA), a 19-carbon steroid, is situated along the steroid metabolic pathway. It is the most abundant circulating hormone in the body and can be converted to either androgens or estrogens. It is readily conjugated to its sulphate ester DHEAS, and they are designated as DHEA(S) here when used together. Its secretion reaches a peak in early adulthood and thereafter decreases, until approximately age 70 years when it reaches a concentration of approximately 20%. Many hormonal changes may take place with aging but none is as marked as this. This "relative DHEA deficiency" resulted in DHEA being enthusiastically labelled by some as a fountain of youth or an antidote to aging that would prove to be the panacea they are seeking. Its use was also taken up enthusiastically by the athletic community and used as a prohormone in the belief or hope that it would be converted mainly to testosterone in the body.

Sexual dimorphism in immune function: the role of prenatal exposure to androgens and estrogens

Perinatal exposure to androgens permanently transforms certain tissues, e.g., the brain, the genitalia, etc. This process involves both masculinization and defeminization. Immune function also is transformed by early steroid exposure; however, it is not yet known whether the response capabilities of the immunocytes themselves are directly modified or whether they are responding to signals from other masculinized tissues, e.g., the brain. Most evidence points to a direct effect since androgen and estrogen receptors are present in developing immunocytes. Both androgens and estrogens have a role in regulating adult immunity including Th1/Th2 balance. Adult susceptibility to autoimmune and other diseases is also related to steroid exposure. How immune cells respond to gonadal steroids in adulthood may depend on the pattern of androgenic and estrogenic stimulation during early development.

Endocrinological aspects of aging in men: is hormone replacement of benefit?

Age-related decreases of serum testosterone (total, free and bioavailable), DHEA, DHEA-S, growth hormone (GH) and IGF-I are well established in elderly healthy men. Although substantial, the decrease of these hormones is small compared to the estrogen changes observed in postmenopausal women. Elderly men also loose bone and muscle, gain fat and have less sexual appetite. Therefore, the assumption that hormonal therapy is a potential 'fountain of youth' appears logical. At present, however, the effects of replacement of testosterone, DHEA and GH in healthy elderly men have been studied in only a few randomised placebo-controlled trials. These studies were small and of short duration. Although some significant overall effects of either androgen or GH replacement on body composition (less fat and more muscle) were found, the effects of such therapy on muscle strength, on metabolic and sexual function and on skeletal homeostasis have been less consistent. Also, the safety of such therapy should be better documented. Moreover, data obtained in healthy elderly men cannot be transposed to non-healthy elderly men. In conclusion, more scientific work is needed before general replacement of the 'falling hormones' should be regarded as beneficial for elderly men.