Transport of dehydroepiandrosterone and dehydroepiandrosterone sulphate into rat hepatocytes

The purpose of the present study was to characterize the transport of dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulphate (DHEAS) into hepatocytes at physiological and pharmacological concentrations. Hepatocytes were isolated from female Sprague-Dawley rats by collagenase perfusion. Uptake of [³H]DHEA and [³H]DHEAS at increasing concentrations (3.5 nM-100 μM) was measured by the rapid filtration technique at 30 s intervals up to 120 s. The uptake of DHEAS by hepatocytes was saturable (K_m = 17.0 μM; V_max = 3.7 nmol/min/mg cell protein). In contrast, a specific saturable transport system for DHEA could not be detected in rat hepatocytes. It is suggested that DHEA enters the cell by diffusion. The uptake of DHEAS could be inhibited by antimycin A, carbonylcyanide-m-chlorophenylhydrazone, and dinitrophenol (inhibitors of the mitochondrial respiratory chain), by dinitrofluorobenzene and p-hydroxymercuribenzoate (NH₂- and SH-blockers, respectively), and by monensin (Na⁺-specific ionophore). No inhibition was seen in the presence of ouabain (inhibitor of Na⁺-K⁺-ATPase) and phalloidin (inhibitor of cholate transport and actin-blocker). Interestingly, DHEAS uptake was inhibited by bile acids (cholate, taurocholate and glycocholate). Conversely, [³H]cholate uptake was strongly inhibited by DHEAS, which indicates a competition for the same carrier. Replacement of sodium ion with choline markedly decreased uptake velocity at pharmacological DHEAS concentrations. The results suggest that DHEAS uptake is a saturable, energy-dependent, carrier-mediated, partially Na⁺-dependent process, and that DHEAS may be taken up via the multispecific bile acid transport system.     

A simple, accurate, and sensitive assay method of dehydroepiandrosterone sulfate: application for quantitative determination in human breast cyst and duct fluids

Radioimmunoassay (RIA) is the most prevalent method for measuring small amounts of hormones, peptides, and other compounds in human body fluids. The method, however, has several problems, such as cross reactions or non-specific reactions of the antibody used. In order to establish an improved method for assaying dehydroepiandrosterone sulfate (DHEAS) and cholesterol, which are the largest components of human breast cyst and duct fluids, we describe a simple, accurate, and sensitive method using high-performance liquid chromatography (HPLC). The samples were treated with cholesterol oxidase for quantitation of dehydroepiandrosterone (DHEA) and free cholesterol, and the respective oxidized substances, 4-androstene-3,17-dione and 4-cholesten-3-one, were extracted with n-hexane. The extracts were analyzed by straight phase HPLC. Effluents were monitored by measuring absorption at 240 nm, where a newly introduced chromophoric group, an alpha,beta-unsaturated ketone, showed intense absorption (epsilon = 16,000). When the total amount of DHEA (DHEAS plus DHEA) was measured, the sample had been solvolyzed by sulfatase beforehand. The amounts of DHEAS were quantified by comparing the amounts of DHEA before and after solvolysis. Levels of free cholesterol, DHEAS, and DHEA in human breast cyst fluids (n = 30) were 1.77 +/- 1.12 mmol/dl, 8.27 +/- 10.24 micromol/dl, and 0.02 +/- 0.02 micromol/dl (means +/- SD), respectively. The levels of sterol and steroid measured in breast duct fluids that were turbid, brown, dark green, or milky in color (n = 9) (mean levels, 3.20 +/- 2.97 mmol/dl for free cholesterol and 14.77 +/- 13.75 micromol/dl for DHEAS) were significantly (P < 0.01) higher than the levels in clear or serous breast fluids (n = 21) (mean levels, 0.14 +/- 0.13 mmol/dl for free cholesterol and 0.04 +/- 0.07 micromol/dl for DHEAS).     

Measurement of serum levels of dehydroepiandrosterone sulfate: a comparison of radioimmunoassay and enzymatic analysis

Dehydroepiandrosterone sulfate (DHEAS) and unconjugated dehydroepiandrosterone (DHEA) are secretory products of the adrenal cortex. Measurement of serum levels of these steroids is of increasing epidemiologic interest, since low serum concentrations of DHEAS or DHEA have been associated with an increased risk of dying of cardiovascular disease or of developing cancer. Radioimmunoassays (RIAs) are the most convenient systems for the measurement of serum DHEAS concentrations in multiple samples. However, using sera from four individuals we show that different RIA kits provide quite different estimates of serum DHEAS concentrations. Moreover, these results do not always agree with the serum concentrations determined by an independent chromatographic and enzymatic reference method. The results highlight the need for an independent method of determining DHEAS levels in sera that can provide guidance in selecting an appropriate RIA, and in interpreting the results.     

Physiological levels and action of dehydroepiandrosterone in Yucatan miniature swine

The biological role of dehydroepiandrosterone (DHEA) and its less active sulphated conjugate DHEAS was investigated in two experiments using Yucatan miniature swine. In experiment 1, plasma levels of both DHEA(S) among males were greater than female pigs that ranged in age from 0.3 to 84 mo old (P < 0.0001). In males, DHEA(S) were related inversely to serum triglycerides; DHEA was positively related to triglycerides in females (P < 0.01). In experiment 2, four 2-yr old male pigs, used as their own control, showed a 5% decrease in body weight, 11% increase in energy expenditure, 88% increase in lipid, and 100% decrease in glucose utilization (P < 0.0001) in response to DHEA vs. placebo treatments when adjusted for body weight. Plasma DHEA(S) were not different between treatment conditions. Glucose tolerance and plasma insulin levels were not different from controls. In vivo response to norepinephrine indicated beta-adrenergic sensitivity was altered by DHEA. Present findings suggest DHEA and/or its hormone products are important in modulating energy expenditure and lipid utilization for energy in male animals. The role of DHEA in energy metabolism and the difference between sexes warrant further investigation.     

Plasma dehydroepiandrosterone, its sulfate, testosterone and FSH during puberty of African children in Gabon

Plasma levels of dehydroepiandrosterone (DHEA), its sulfate (DHEAS), testosterone (T) and follicle stimulating hormone (FSH) were measured by radioimmunoassay in 111 schoolboys and 95 schoolgirls from 7 to 18 years. 68 male and 55 female adults aged from 19 to 25 were also investigated. Results are expressed as the mean +/- SD, DHEA was the first hormone to vary showing a significant mean increase between the 10 and 11 year age groups of both boys and girls. Higher levels were observed in the age 12 group (boys 164.70 +/- 60.74; girls 256.60 +/- 145.40 ng/dl) but were followed by a significant decrease in both 13 year old groups. Similar increases followed by decreases were also noted for DHEAS, although the increase started between 11 and 12 years and reached a maximum at 13. An abrupt increase in FSH levels between 11 and 12 years followed by a plateau through 15-18 years, was observed for boys and girls. As expected, T levels increasing significantly in boys with the initial rise between 11 and 12 and a climb through to the 15-18 age group. Our results suggest a late plasma DHEAS secretion with adult levels attained after age 19. Menarche was also found to be late.     

Skeletal muscle differentiation: role of dehydroepiandrosterone sulfate

Dehydroepiandrosterone (DHEA) and its sulfonated form dehydroepiandrosterone sulfate (DHEAS) are the main circulating steroid hormones and many epidemiological studies show an inverse relationship between DHEA/DHEAS levels and muscle loss for which the primary cause is the accelerated protein breakdown. The aim of this work was to determine whether DHEA/DHEAS supplementation in differentiating C2C12 skeletal muscle cells might influence the expression of the atrophy-related ubiquitin ligase, MuRF-1, and thereby impact key molecules of the differentiation program. DHEA is the prohormone crucial for sex steroid synthesis, and DHEAS is thought to be its reservoir. However, our preliminary experiments showed that DHEAS, but not DHEA, is able to influence MuRF-1 expression. Therefore, we treated differentiating C2C12 cells with various concentrations of DHEAS and analyzed the expression of MuRF-1, Hsp70, myosin heavy chain (MHC), myogenin, and the activity of creatine kinase. We observed that DHEAS at physiological concentrations downregulates MuRF-1 expression and affects muscle differentiation, as shown by the increased levels of MHC, which is a sarcomeric protein that undergoes MuRF-1-dependent degradation, and also by an increase in creatine kinase activity and myogenin expression, which are two other well-known markers of differentiation. Moreover, we found that DHEAS might have a protective effect on differentiating cells as suggested by the augmented levels of Hsp70, a member of heat shock proteins family that, besides its cytoprotective action, seems to have a regulatory role on key atrophy genes such as MuRF-1. In conclusion, our data shed light on the role of DHEAS at physiologic concentrations in maintaining muscle mass.     

Influence of intestinal bacterial desulfation on the enterohepatic circulation of dehydroepiandrosterone sulfate

Selective association of germ-free (GF) rats with dehydroepiandrosterone sulfate (DHEAS) desulfating bacteria allowed us to assess the exact impact of intestinal bacterial desulfation on the excretion and enterohepatic circulation of orally administered DHEAS. Germ-free rats selectively associated with the DHEAS-desulfating strain Peptococcus niger H4 (H4 rats) excreted 50% of the total label recovered within 17 h vs 21 h in GF rats and 13 h 23 min in conventional (CV) rats. Germ-free rats excreted 30% of the total label recovered via their urine. However, association of GF rats with the desulfating microorganism increased urinary excretion to 46%, comparable to the 45.5% found in CV rats. Fractionation of fecal label yielded 70% sulfoconjugated DHEAS and 2% unconjugated dehydroepiandrosterone in GF rats vs 5 and 77% in CV rats, and 55 and 14% in H4 rats, respectively. Our results demonstrate that the intestinal bacterial desulfation of DHEAS stimulated the enterohepatic circulation of DHEAS. This in turn increased the urinary excretion of label resulting in an accelerated elimination of labeled DHEAS from the body.     

Antioxidant activity of dioscorea and dehydroepiandrosterone (DHEA) in older humans

Dioscorea is a yam steroid extract used in commercial steroid synthesis and consumed by people. DHEA is a steroid which declines with age, but without known activity. This study was designed to determine whether dioscorea supplementation could increase serum dehydroepiandrosterone sulfate (DHEAS) in humans and modulate lipid levels in older people. The subjects were selected volunteers aged 65–82 years. The serum DHEAS level, lipid peroxidation and lipid profile were assessed. Three weeks of dioscorea supplementation had no affect on serum DHEAS level. However DHEA intake of 85 mg/day increased serum DHEA levels 100.3 %. DHEA and dioscorea significantly reduced serum lipid peroxidation, lowered serum triglycerides, phospholipid and increased HDL levels. Both DHEA and the steroid yam extract, dioscorea, have significant activities as antioxidant to modify serum lipid levels.     

Effect of ACTH and prolactin on dehydroepiandrosterone, its sulfate ester and cortisol production by normal and tumorous human adrenocortical cells

The effect of ACTH and prolactin on the synthesis of dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) was studied in cell suspensions of "normal" and tumorous (adenoma) human adrenal cortex. A stimulation of DHEA and no response of DHEAS production by ACTH in "normal" adrenocortical cell suspension was observed. However ACTH stimulated both DHEA and DHEAS synthesis in tumorous adrenocortical cells. Prolactin did not influence either the basal or the ACTH stimulated DHEA and DHEAS production of adrenocortical cells irrespective of their origin. Our results are compatible with the concept that the biosynthesis of DHEA is under ACTH control, while other factor(s) regulate(s) the sulfate pathway of DHEA secretion under normal conditions. In tumorous adrenocortical cells DHEA may be regulated--at least partly--by ACTH. Prolactin seems to have no direct effect on DHEA and DHEAS synthesis. It is postulated that the relationship between serum prolactin and DHEAS (or DHEA) levels observed by several authors might be an extraadrenal effect of prolactin on adrenal androgens.     

Characterization of serum dehydroepiandrosterone secretion in golden hamsters

Dehydroepiandrosterone (DHEA) is an adrenal androgen whose function is poorly understood. Although DHEA and DHEA sulfate (DHEAS) are secreted in relatively high quantities by the human adrenal, the laboratory rat secretes very little, thus hindering experimental studies of the hormone. In this paper, we measured the changes in serum DHEA and DHEAS under various physiological conditions in golden hamsters. Evening serum DHEAS fell from 6.30 +/- 0.78 microg/dl (mean +/- SE) before surgery to 3.03 +/- 0.23 microg/dl 12 days after bilateral adrenalectomy. Hamsters had higher levels of DHEA and DHEAS in the evening than in the morning, but removal of the gonads did not consistently decrease serum DHEA or DHEAS in males or females. Evening levels of DHEA and DHEAS reached a peak around 7 weeks of age and then gradually decreased to about one-third of these levels by one year of age. These results suggest that DHEA and DHEAS are secreted at least in part from the hamster adrenal, that they do not originate from the gonads, and that there is a daily rhythm with peak levels at a time of day just preceding the active phase. In addition, the levels of these hormones decrease with aging.     

Induction of peroxisomal beta-oxidation enzymes by dehydroepiandrosterone and its sulfate in primary cultures of rat hepatocytes.

Treatment of cultured rat-hepatocytes with 50 microM dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) for up to 5 days resulted in a progressive increase in peroxisomal beta-oxidation and carnitine acetyltransferase activity. After 5 days, the increases in activity were 2.6- and 4.8-fold for peroxisomal beta-oxidation and 11.7- and 17.1-fold for carnitine acetyltransferase over the initial activity, in DHEA- and DHEAS-treated cells, respectively. The stimulation of the activity of these enzymes by the respective agents was dose-related; it was maximum with 50 to 100 microM DHEA and 50 to 250 microM DHEAS, although DHEAS was more effective for stimulation than DHEA. Western blot analyses revealed the induction of acyl-CoA oxidase, enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase bifunctional enzyme and carnitine acetyltransferase in the treated cells. Moreover, induction of fatty acid omega-hydroxylase proteins (P-450IVAS) was also revealed. These results indicate that DHEA and DHEAS act directly on hepatocytes. The induction of hepatic peroxisomal beta-oxidation enzymes and several other enzymes in rats administered with DHEA could be accounted for, at least in part, by the direct action of DHEA and its sulfate-conjugate (DHEAS) on liver cells.     

A radioimmunoassay for serum dehydroepiandrosterone sulfate

A radioimmunoassay for serum dehydroepiandrosterone sulfate (DHEAS) (1) has been developed using anti-DHEA antiserum obtained by immunizing rabbits with DHEA-17 oxime-bovine serum albumin. Serum volume of 0.01 to 0. 1 ml was used for analysis. After the addition of ammonium salt of DHEA-7³ H sulfate for recovery and a preliminary removal of DHEA, DHEAS was extracted as pyridinium salt by methylene chloride. The dried extract was subjected to solvolysis (Burstein & Lieberman), followed by paper chromatography. The eluates and DHEA-7 ³H which was added to determine the % free of DHEA were evaporated and incubated with the antiserum containing pepsin treated human immune serum globulin and bovine serum albumin at 37°C for 1 hour. Ammonium sulfate was used to separate free from bound DHEA. The accuracy, precision and specificity were satisfactory. The sensitivity was 3 ng per sample. The blank values could not be differentiated from zero. Although the antiserum reacts with the other 3βOHΔ⁵ steroids as well as DHEA, the complete separation of DHEA from the other 3βOHΔ⁵ steroids was achieved chromatographically. Serum DHEAS levels in normal subjects and patients with adrenocortical disorders obtained with the radioimmunoassay were comparable to those obtained with gasliquid chromatography.     

The pathophysiological implications of circulating androgens on bone mineral density in a normal female population

In this cross-sectional study performed on 147 healthy or osteoporotic, but otherwise normal premenopausal (n = 26 and n = 13, respectively) or postmenopausal (n = 40 and n = 68, respectively) women aged 40.1+/-9.9 and 61.9+/-8.9 years, respectively (range 20-82 years), serum ovarian and adrenal sex steroids and their relationship to bone mineral density (BMD) were evaluated. The levels of dehydroepiandrosterone sulfate (DHEAS), dehydroepiandrosterone (DHEA), androstenedione (AD), and estradiol correlated positively with BMD at the hip and spine as did serum testosterone with BMD at the spine. An inverse relationship was found between sex hormone binding globulin (SHBG) levels and BMD at the spine and hip. After adjustment for age, body mass, and sex steroid confounders, the bioavailable testosterone value (but not the DHEAS, DHEA, AD, or SHBG) values was demonstrated to be an independent determinant of BMD at the spine (beta 0.18, P<0.02) and hip (beta 0.24, P<0.02). Similarly, estradiol was found to be an independent determinant of BMD at the spine (beta 0.25, P<0.007). However, only SHBG levels (but not other steroid parameters) correlated positively with indices of bone remodeling, namely, serum osteocalcin and cross-linked telopeptide of type I collagen (ICTP). The present study suggests that a major decline in index of free testosterone (testosterone/SHBG) may influence the development of female osteoporosis. The clinical significance of circulating SHBG levels in the assessement of bone metabolic turnover remains to be established.     

Decrease in serum dehydroepiandrosterone level after fenofibrate treatment in males with hyperlipidemia

The influence of steroid hormones on plasma lipids and lipoproteins was confirmed by many studies. On the other hand, the effect of plasma lipids on metabolism of steroid hormones has so far not been examined. The objective of this research project was to determine (1) the levels of cortisol, testosterone, estradiol, dehydroepiandrosterone (DHEA), its sulfate (DHEAS), 7-hydroxylated DHEA, and SHBG in men suffering from mixed hyperlipidemia (HPL) (n=23, age 46.1+/-7.9 years) in comparison with healthy male volunteers (n=17, age 45.1+/-15.6 years); (2) whether therapy with fenofibrate influences the levels of the above mentioned steroids and SHBG; (3) what are the correlations between lipids and steroids in healthy males and HPL patients before and after therapy. Compared to controls, untreated patients had significantly higher estradiol and free testosterone index (IFT) levels (p<0.0003 and p<0.02, respectively) and significantly lower SHBG (p<0.02). Due to fenofibrate therapy, a significant decrease of TC, TG, and DHEA levels occurred (mean decrease: 14 %, 52 % and 21 %, respectively). Triglycerides correlated negatively with testosterone and SHBG in healthy subjects. HDL-C correlated positively and consequently, atherogenic index correlated negatively with 7-hydroxylated epimers of DHEA in treated patients. This is the first study dealing with the influence of fenofibrate administration on the steroid levels. Taking together, the most important is the finding of decrease DHEA levels after fenofibrate therapy. It could be explained, at least in part, by the effect of the fenofibrateon on the biosynthesis of DHEA and its regulation.     

Influence of oral dehydroepiandrosterone (DHEA) on urinary steroid metabolites in males and females

Oral dehydroepiandrosterone (DHEA) replacement therapy may have a multitude of potential beneficial effects and exerts its action mainly via peripheral bioconversion to androgens (and estrogens). A daily dose of 50-mg DHEA has been shown by us and others to restore low endogenous serum DHEA concentrations to normal youthful levels followed by an increase in circulating androgens and estrogens. As the hepatic first-pass effect may lead to a non physiological metabolism of DHEA after oral ingestion we studied the influence of two single DHEA doses (50 and 100 mg) on the excretion of steroid metabolites in 14 elderly males [age 58.8+/-5.1 years (mean +/- SEM)] with endogenous DHEAS levels <1500 ng/ml and in 9 healthy females (age 23.3+/-4.1 years) with transient suppression of endogenous DHEA secretion induced by dexamethasone (dex) pretreatment (4x0.5 mg/day/4 days). Urinary steroid profiles in the elderly males were compared to the steroid patterns found in 15 healthy young men (age 28.9+/-5.1 years). In the females the results were compared to their individual baseline excretion without dex pretreatment. Urinary steroid determinations were carried out by semiautomatic capillary gas-liquid chromatography. In both genders DHEA administration induced significant increases in urinary DHEA (females: baseline vs. 50 mg vs. 100 mg: 361+/-131 vs. 510+/-264 vs. 1541+/-587 microg/day; males: placebo vs. 50 mg vs. 100 mg: 434+/-154 vs. 1174+/-309 vs. 4751+/-1059 microg/day) as well as in the major DHEA metabolites androsterone (A) and etiocholanolone (Et). Fifty mg DHEA led to an excretion of DHEA and its metabolites only slightly above baseline levels found in young females and in young men, respectively, whereas 100 mg induced clearly supraphysiological values. After 50 mg DHEA the ratios of urinary DHEA metabolites (A/DHEA, Et/DHEA) were not significantly different between elderly males vs. young male volunteers and young healthy females versus their individual baseline levels. In conclusion, an oral dose of 30 to 50 mg DHEA restores a physiological urinary steroid profile in subjects with DHEA deficiency without evidence for a relevant hepatic first-pass effect on urinary metabolites.     

Adrenal androgen concentrations increase during infancy in male rhesus macaques (Macaca mulatta)

This study investigated adrenal androgens (AA), gonadotropins, and cortisol in castrated and gonad-intact male rhesus macaques from birth through infancy. Blood samples were collected longitudinally from castrated (n = 6; weekly, 1-40 wk) and intact (n = 4; every other week, 1-17 wk) males. Plasma concentrations of AA were determined by liquid chromatography-tandem mass spectrometry, and plasma concentrations of cortisol and gonadotropins were determined by RIA. Dehydroepiandrosterone sulfate (DHEAS) concentrations increased almost threefold (to 8 wk), dehydroepiandrosterone (DHEA) increased more than eightfold (to 11 wk), and androstenedione doubled (to 15 wk) in five castrated infant males and declined continuously thereafter. A sixth castrated male had markedly different temporal patterns and concentrations (many times more than 2 SDs from the cohort mean) of AA and gonadotropins from first sampling (3 wk) and was excluded from analysis. Cortisol increased over 16 wk but correlated poorly with DHEAS. Luteinizing and follicle-stimulating hormones increased to peaks at 3 and 7 wk, respectively. Testis-intact males exhibited similar profiles, but with earlier peaks of DHEAS (5 wk) and DHEA and androstenedione (7 wk). Peak concentrations of DHEAS were lower and those of DHEA and androstenedione were higher in intact than castrated infants. Testosterone was undetectable in castrated males and >0.5 ng/ml in intact males but was not correlated with DHEA or DHEAS. These are the first data documenting a transient increase in AA secretion during infancy in an Old World primate and are consistent with the previously documented time course of zona reticularis development that accompanies increases in androgen synthetic capacity of the adrenal. The rhesus is a promising model for androgen secretion from the human adrenal cortex.     

Simultaneous determination of dehydroepiandrosterone, its 7-hydroxylated metabolites, and their sulfates in rat brain tissues

A method is described for simultaneous assessment of dehydroepiandrosterone (DHEA), its sulfate (DHEAS), and their 7-hydroxylated metabolites in cortex and subcortex of the rat brain. The procedure for determination of unconjugated steroids and DHEAS involved diethyl ether extraction of the homogenized tissue, solvent partition of the dry extract, and final quantification by specific radioimmunoassays. In addition, determination of 7-hydroxy-dehydroepiandrosterone sulfates required solvolysis, followed by high-performance liquid chromatography for separation of 7-hydroxylated metabolites from their precursor. The losses during this process were monitored by measurement of spiked radioactivity of [(3)H]testosterone or [(3)H]dehydroepiandrosterone sulfate. The content of dehydroepiandrosterone sulfate in both brain tissues was of the order of ten(s) nmol/g tissue irrespective its type (cortex or subcortex), while concentrations of other steroids were about 10 times lower in both tissues. In contrast to the ratio of sulfated/unconjugated DHEA, the levels of unconjugated 7-hydroxylated metabolites and their sulfates were close to each other. The reproducibility of the method with respect to coefficients of variation varied from 12 to 25%. An age-related decrease of sulfated dehydroepiandrosterone in the cortex of animals was also observed.     

Simplified procedure for measurement of serum dehydroepiandrosterone and its sulfate with gas chromatography–ion trap mass spectrometry and selected reaction monitoring

Dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) are endogenous steroids that have recently been widely publicized as potential treatments for many disorders. This paper describes a gas chromatographic–ion trap mass spectrophotometric assay with selected reaction monitoring for measurement of DHEA and DHEAS levels. The hormones and internal standard (5-androsten-3β-ol-16-one methyl ester) are extracted from serum with Oasis solid-phase extraction tubes. The extracted steroids are dissolved in methanol and injected into a Finnigan GCQ ion trap mass spectrometer. In the selected reaction mode, both DHEA and DHEAS can be identified and quantified in a single injection. No derivatization or expensive deuterated internal standards are required.     

Effects of transdermal application of DHEA on the levels of steroids, gonadotropins and lipids in men

In order to ascertain the kinetics of absorption and metabolism of transdermally administered dehydroepiandrosterone (DHEA), 10 men 29-72 years old (mean 52.4+/-14.5) received 50 mg DHEA/day in a gel applied onto the skin of the abdomen for 5 consecutive days. The objective was to establish the extent to which DHEA influences the levels of gonadotropins, sex hormone-binding globulin and lipids. It was found that DHEA is well absorbed and rapidly metabolized to its sulfate (DHEAS), androstenedione, and consequently to testosterone and estradiol. The DHEA levels that markedly increased after the first doses gradually declined already during the application, and this decline proceeded even after it was discontinued, reaching levels significantly lower than the original ones. On the other hand, the levels of DHEA metabolites (with the exception of DHEAS) rose during the application and reached values significantly higher than the basal ones within 5 weeks. This effect was accompanied by significantly decreased levels of LH. The serum levels of lipids, namely of cholesterol (both HDL and LDL cholesterol), triglycerides, apolipoproteins A-I and B and lipoprotein(a) after DHEA application were not changed significantly, and the atherogenic index (AI) remained unaltered. However, some correlations between hormones and lipids were found. Negative correlations concerned the following indices: DHEA/Lp(a); DHEAS/cholesterol; DHEA, DHEAS, testosterone/TG; testosterone/AI. On the other hand, LH, FSH/cholesterol, FSH, SHBG/LDL cholesterol, FSH/Apo B, Lp(a) correlated positively. It can be concluded that transdermal short-time application of DHEA results in a decrease of endogenous DHEA after finishing the treatment, with a parallel marked increase in the levels of sex hormones. Using this application protocol, exogenous DHEA neither altered the lipid spectrum, nor did it influence the atherogenic index.     

Increased muscular dehydroepiandrosterone levels are associated with improved hyperglycemia in obese rats

This study was undertaken to assess the effects of dehydroepiandrosterone (DHEA) administration and exercise training on muscular DHEA and 5α-dihydrotestosterone (DHT) levels and hyperglycemia in diet-induced obese and hyperglycemic rats. After 14 wk of a high-sucrose diet, obese male Wistar rats were assigned randomly to one of three 6-wk regimens: control, DHEA treatment, or exercise training (running at 25 m/min for 1 h, 5 days/wk; n = 10 each group). Results indicate that either 6 wk of DHEA treatment or exercise training significantly attenuated serum insulin and fasting glucose levels compared with the control group. Plasma and muscle concentrations of DHEA and DHT and expression levels of 5α-reductase were significantly higher in the DHEA-treated and exercise-training groups. Moreover, both DHEA administration and exercise training upregulated GLUT4 translocation with concomitant increases in protein kinase B and protein kinase Cζ/λ phosphorylation. Muscle DHEA and DHT concentrations closely correlated with blood glucose levels (DHEA treatment: r = -0.68, P < 0.001; exercise training: r = -0.65, P < 0.001), serum insulin levels, and activation of the GLUT4-regulated signaling pathway. Thus, increased levels of muscle sex steroids may contribute to improved fasting glucose levels via upregulation of GLUT4-regulated signaling in diet-induced obesity and hyperglycemia.