A radioimmunoassay for serum dehydroepiandrosterone sulfate

Dehydroepiandrosterone sulfate (DHEAS) stimulates the first step in the biosynthesis of steroid hormones

Dehydroepiandrosterone sulfate (DHEAS) is the most abundant circulating steroid in human, with the highest concentrations between age 20 and 30, but displaying a significant decrease with age. Many beneficial functions are ascribed to DHEAS. Nevertheless, long-term studies are very scarce concerning the intake of DHEAS over several years, and molecular investigations on DHEAS action are missing so far. In this study, the role of DHEAS on the first and rate-limiting step of steroid hormone biosynthesis was analyzed in a reconstituted in vitro system, consisting of purified CYP11A1, adrenodoxin and adrenodoxin reductase. DHEAS enhances the conversion of cholesterol by 26%. Detailed analyses of the mechanism of DHEAS action revealed increased binding affinity of cholesterol to CYP11A1 and enforced interaction with the electron transfer partner, adrenodoxin. Difference spectroscopy showed K_d-values of 40±2.7 µM and 24.8±0.5 µM for CYP11A1 and cholesterol without and with addition of DHEAS, respectively. To determine the K_d-value for CYP11A1 and adrenodoxin, surface plasmon resonance measurements were performed, demonstrating a K_d-value of 3.0±0.35 nM (with cholesterol) and of 2.4±0.05 nM when cholesterol and DHEAS were added. Kinetic experiments showed a lower K_m and a higher k_cat value for CYP11A1 in the presence of DHEAS leading to an increase of the catalytic efficiency by 75%. These findings indicate that DHEAS affects steroid hormone biosynthesis on a molecular level resulting in an increased formation of pregnenolone.

Serum dehydroepiandrosterone sulfate levels predict longevity in men: 27-year follow-up study in a community-based cohort (Tanushimaru study)

OBJECTIVES

To determine whether serum dehydroepiandrosterone sulfate (DHEAS) levels could predict longevity in residents.

DESIGN

Prospective community-based cohort study.

SETTING

Community.

PARTICIPANTS

Nine hundred forty subjects (396 men, 544 women; aged 21 to 88) underwent a health examination in 1978. Serum DHEAS levels were measured according to radioimmunoassay at baseline in all subjects, and subjects were followed periodically until 2005.

RESULTS

Baseline DHEAS levels were higher in men than in women and decreased with age in both sexes. In a Cox proportional hazards model, age, DHEAS (inversely), blood pressure, and fasting plasma glucose were significantly associated with shorter longevity in men but not in women. Of these variables, high DHEAS levels in men were the strongest predictor of longevity (beta=-2.032, hazard ratio=0.131, 95% confidence interval=0.029-0.584 in the Cox proportional hazards model after adjustment for age). The Kaplan-Meier survival curve, stratified according to tertiles of DHEAS levels, in men after adjustments for age, systolic blood pressure, and fasting plasma glucose showed significantly (log-rank stat =10.6; P<.001) greater longevity in the highest group (200 microg/dL) than in the moderate (130-199 microg/dL) or lowest groups (129 microg/dL).

CONCLUSION

This 27-year study in a community-based cohort indicated that DHEAS level may be a predictor of longevity in men, independent of age, blood pressure, and plasma glucose.

Marked attenuation of production of collagen type I from cardiac fibroblasts by dehydroepiandrosterone

Dehydroepiandrosterone (DHEA) is a type of adrenal steroid. The concentrations of DHEA and its sulfate (DHEA-S) in serum reach a peak between the ages of 25 and 30 yr and thereafter decline steadily. It was reported that DHEA-S concentration in humans is inversely related to death from cardiovascular diseases. In this study, we examined the effects of DHEA on regulation of collagen mRNA and collagen synthesis in cultured cardiac fibroblasts. Treatment with DHEA (10(-6) M) resulted in a significant decrease in procollagen type I mRNA expression compared with controls. This was accompanied by a significant decrease in procollagen type I protein accumulation in the medium and also a significant decrease in procollagen type I protein synthesis in the cellular matrix. Furthermore, to confirm in vitro results, we administered DHEA to Sprague-Dawley rats, which were treated with angiotensin II for 8 wk to induce cardiac damage. Procollagen type I mRNA expression was significantly decreased and cardiac fibrosis significantly inhibited in DHEA-treated rat hearts without lowering the systolic blood pressure. These results strongly indicate that DHEA can directly attenuate collagen type I synthesis at the transcriptional level in vivo and in vitro in cardiac fibroblasts.

Determination of 17-oxosteroid sulphates in serum by ion-pair extraction, prelabelling with dansylhydrazine and high-performance liquid chromatography with fluorescence detection

A new high-performance liquid chromatographic (HPLC) method with fluorescence detection is described for the direct determination of four serum 17-oxosteroid sulphates. Each serum sample was deproteinated with methanol, the methanol was evaporated and 17-oxosteroid sulphates in the residue were extracted with benzene as ion pairs in the presence of tetrapentylammonium ion. The ion pairs were labelled with dansylhydrazine and the hydrazones were separated by HPLC on a Capcell-Pak C8 (silicone polymer-coated silica gel modified with octyl groups) reversed-phase column using methanol-0.5% (w/v) sodium acetate-50% (v/v) acetic acid (57:42:1, v/v/v) as the mobile phase. The eluent was monitored with a fluorometric detector at an excitation wavelength of 330 nm and an emission wavelength of 540 nm.

Serum dehydroepiandrosterone sulfate in a normal pediatric population

Dehydroepiandrosterone sulfate (DHAS) was measured in serum from 274 children and adolescents aged 1 month to 18.7 years, and in 38 healthy adults. In the pediatric group, which comprised 131 males and 143 females, serum DHAS was markedly age-dependent. Values declined between 1 and 5 months after birth, but were generally less than 4 mumol/L. Between 6 months and 7 years DHAS was less than 0.5 mumol/L in boys and less than 1.0 mumol/L in girls. Above 8 years DHAS progressively increased in both sexes to less than 13 mumol/L in mid-late teenage males and less than 12 mumol/L in females of the same age, similar to the values observed in the adults. In children and adolescents over 10 years, there was considerable overlap in DHAS values between groups of children classified by pubertal stage, resulting from the dissociation between adrenal and gonadal development during normal puberty.

Studies on steroids. CC. Determination of 17-ketosteroid sulphates in serum by high-performance liquid chromatography with electrochemical detection using pre-column derivatization

A new sensitive method is described for the determination of 17-ketosteroid sulphates, particularly dehydroepiandrosterone sulphate, in human serum by high-performance liquid chromatography with electrochemical detection. The 17-ketosteroid sulphates in serum were extracted with acetonitrile and derivatized with p- nitrophenylhydrazine in trichloroacetic acid--benzene solution. The p- nitrophenylhydrazones were separated by high-performance liquid chromatography on a mu Bondapak C18 column using methanol--0.5% ammonium dihydrogen phosphate (8:3) as a mobile phase. The proposed method proved to be applicable to the quantitation of 17-ketosteroid sulphates with satisfactory sensitivity and reliability, providing a quantitation limit of 80 ng/ml and coefficient of variation of 4%. A good correlation was observed between the values obtained by the present method and radioimmunoassay for dehydroepiandrosterone sulphate in serum.

Enzymatic determination of dehydroepiandrosterone sulfate in biological fluids

A simple method is described for the determination of androgens, particularly dehydroepiandrosterone sulfate (DHEAS), in human plasma and urine. The method does not involve extraction or chromatography. An internal standard is used as reference. The androgens are enzymatically converted to estrogens and these latter compounds can be measured by the enzymatic method previously described [1]. The range of accuracy was between 99 and 103%. The precision of the method was 2.5%. The sensitivity was 0.1 pM per sample. The method is suitable for routine use, and one worker can easily perform twenty assays in one day.

Spermatic and peripheral venous plasma concentrations of dehydroepiandrosterone sulfate in prepubertal and pubertal boys

Dehydroepiandrosterone sulfate (DEAS), a major adrenal product, is quantitatively one of the most important steroids found in human testicular tissue. However, conflicting data have been reported about the testicular production of DEAS 'in vivo'. We have measured the spermatic and peripheral concentrations of testosterone (T) and DEAS in two groups of prepubertal (Group I, N = 18) and pubertal (Group II; N = 11) boys undergoing surgery for undescended testis, inguinal hernia or varicocele. Mean (+/- SE) spermatic concentrations of DEAS (77 +/- 16 and 113 +/- 19 micrograms/dl in Group I and II respectively) were not significantly different from peripheral concentrations (70 +/- 13 and 130 +/- 16 micrograms/dl in Group I and II respectively). Mean spermatic concentrations of T (153 +/- 101 and 7515 +/- 4314 ng/dl in Group I and II respectively) were significantly different from peripheral concentrations (9 +/- 1 and 149 +/- 53 ng/dl; P less than 0.001 in both groups). Spermatic and peripheral levels of T and DEAS found in prepubertal boys were significantly lower than those found in pubertal boys. Spermatic levels of DEAS were not significantly related with spermatic levels of T in both groups. Our data show that, as in adult subjects, no significant spermatic-peripheral DEAS gradient is present in prepubertal and pubertal boys.

Estrone sulfate and dehydroepiandrosterone sulfate concentrations in normal subjects and men with cirrhosis

Circulation levels of estrone sulfate (E1S) and dehydroepiandrosterone sulfate (DHAS) have been measured in plasma using a radioimmunoassay for estrone and dehydroepiandrosterone following extraction and hydrolysis of the sulfate. The mean +/- SE concentrations of E1S and DHAS in normal men were 458 +/- 25 pg/ml and 1.45 +/- 0.19 micrograms/ml, respectively. In normal women the values for days 5-7 of the cycle were 880 +/- 117 pg/ml and 1.25 +/- 0.12 micrograms/ml which were not different than the values for days 20-22 of 1195 +/- 176 pg/ml and 1.58 +/- 0.29 micrograms/ml. The mean values in post-menopausal women were 250 +/- 33 pg/ml and 0.47 +/- 0.07 micrograms/ml, both lower than the values in young women. In a group of cirrhotic men the mean values were 325 +/- 55 pg/ml and 0.38 +/- 0.12 micrograms/ml, both significantly lower than the normal values. This suggests a defect in sulfurylation in men with hepatic cirrhosis.

Evidence for existence of cortical androgen-stimulating hormone

An animal model using dexamethosone-suppressed, castrated dogs was developed to test the hypothesis that a pituitary hormone other than ACTH modulates adrenal androgen (AA) secretion. Plasma samples were obtained every 15 min during infusions of saline, synthetic alpha 1-24 corticotropin, porcine 1-39 corticotropin (ACTH), or bovine pituitary gland extract (PE) in a wide range of doses. Androstenedione (A), dehydroepiandrosterone (DHA), and cortisol (F) were quantified by radioimmunoassay. When the ratio of AA levels was related to those of F, in order to correct for ACTH content in the PE, the slopes of the dose-response curves for corticotropin and PE were different at the 0.01 level. For A the dose-response slope for the PE was 0.18 +/- 0.5 SE, whereas that of ACTH was 0.02 +/- 0.01. For the DHA response the slopes were 0.17 +/- 0.04 for the PE and 0.04 +/- 0.03 for ACTH. Related studies showed no increase in AA levels in response to luteinizing hormone-releasing hormone, bovine growth hormone (GH), bovine prolactin, ovine thyroid-stimulating hormone (TSH), or synthetic aqueous arginine vasopressin (AVP). We conclude that a pituitary factor other than ACTH, prolactin, GH, luteinizing hormone, follicle-stimulating hormone, TSH, or AVP may be responsible for the observed increase in AA concentrations.

Radioimmunoassay of androsterone and androsterone-3-sulfate in plasma

Details of a sensitive and specific radioimmunoassay for androsterone (1) and androsterone sulfate in plasma have been presented. Benzene extracts of plasma were chromatographed on alumina to isolate the androsterone fraction either (a) directly after extraction (A) or (b) after solvolysis (AS). Following treatment with rabbit anti-A-17-BSA, antibody bound steriod was precipitated by ammonium sulfate. Androsterone concentrations in normal male plasma averaged 57 +/- 24 (S.D.) ng/dl, range 35-135 ng/dl and for normal women, 44 +/- 21 (S.D.) ng/dl, range 18-98 ng/dl. Androsterone sulfate concentrations were: males 55 +/- 28 mug/dl (range 10-114 mug/dl); premenopausal females 52+/- 31 mug/dl (range 16-318 mug/dl).

A rapid radioimmunoassay for determination of dehydroepiandrosterone sulphate in human plasma

A rapid radioimmunoassay for the determination of dehydroepiandrosterone sulphate (DHEA-S) in diluted human plasma is described. The radioimmunoassay is performed using an antiserum to DHEA-3-hemisuccinate-BSA. A charcoal-dextran mixture is used for separation of the bound from the free fraction. The reliability criteria of the method in terms of precision, accuracy, sensitivity and specificity have been evaluated. The mean level of DHEA-S in plasma samples from normal men (age range 24-37) is 241-5+/-72-5 mug/dl. In normal premenopausal women the highest values are in the second third of the menstrual cycle (corresponding to the ovulatory phase). In normal old men (age range 64-86) and in post-menopausal women (age range 55-88) the mean values are, respectively, 51-9+/-33-8 and 53-8+/-34-0. The DHEA-S levels found in several cases of adreno-cortical disorders are reported. In primary adrenal insufficiency and in Cushing's syndrome due to adrenal adenoma or bilateral multinodular hyperplasia low values are found; in Cushing's syndrome due to bilateral adrenal hyperplasia normal values are usually found.