Does adrenal cortex influence prolactin secretion? Evaluation in hirsute women

To define the role of adrenal hormones on PRL secretion, we investigated 28 women by administering i.v. 0.25 mg. ACTH (h 8.00) every 45' for 135' to better evaluate any relationship between enhanced adrenal steroidogenic activity (both glycoactive and androgenic) and PRL secretion. Blood samples were drawn at 0', 45', 90', 135', and PRL, F, DHEAS, and 170HP were measured by RIA methods. A significant lowering of PRL levels and a concomitant enhancement of steroid plasma levels were found. Our data are in line with those found by some Authors who observed the lack of PRL enhancement after hypoglycemia during glucocorticoid administration and the absence of nocturnal peak of PRL in patients with Cushing's disease. However statistical evaluation (linear analysis regression) of data obtained provides further evidence for the extremely influential role played by adrenal gland hormones on PRL secretion in women.     

Helpful diagnostic markers of steroidogenesis for defining hyperandrogenemia in hirsute women

HYPOTHESIS: Androgen excess carries varied clinical manifestations in women. Although testosterone and dehydroepiandrostendionesulfate (DHEAS) determination is considered useful in diagnostic workup, there is no laboratory definition that sufficiently describes androgen excess. DESIGN: We studied 464 hirsute women with a Ferriman and Gallwey score of at least 8 between 2000 and 2005. Our examination included clinical data, total testosterone (T), sex hormone-binding globulin (SHBG), the free androgen index (FAI), and DHEAS. Additionally, androstendione, 17alpha-hydroxyprogesterone (17OHP), dehydroepiandrostendione (DHEA), and 11-deoxycortisol were determined at baseline and 60min after corticotropin challenge (250microg synacthen). RESULTS: Of 464 women, 77.6% fulfilled the clinical criteria for hyperandrogenemia. Of these 360 women, 78.1% had hyperandrogenic hirsutism. Of these 281 women, 43.4% showed increased stimulation of 17OHP to 250microg of synacthen. Another 37.4% showed adrenal steroid biosynthesis defects other than 21alpha-hydroxylase deficiency, such as defective 11beta-hydroxylation or 3beta-hydroxysteroid dehydrogenase malfunction. The diagnosis of polycystic ovary syndrome was applicable to 12.4%. In addition, our results show that 72% of 281 patients with secondary hirsutism had normal T concentrations, and 55% had a normal FAI. Only 5% of hirsute patients with a normal FAI had elevated DHEAS values. However, 40% showed elevated DHEA levels, while 26% of the women with normal FAI showed androstendione values over the maximal levels in the 79 controls. CONCLUSIONS: Our data suggest that in addition to testosterone and FAI, androstendione and DHEA are significantly helpful parameters in diagnosing hyperandrogenemia in hirsute women. DHEAS was not found to be helpful.     

The effect of ACTH administration on plasma testosterone, dihydrotestosterone and serum LH concentrations in normal men

Plasma cortisol (F), testosterone (T), dihydrotestosterone (DHT) and serum luteinizing hormone (LH) concentrations were measured in 8 normal young men at 8 AM on two control days. Exogenous adrenocorticotrophin (ACTH) 20 U.S.P. units per m² of body surface area every 12 or 6 hours was administered intramuscularly for 4 days. Twenty-four hours after starting ACTH administration, the plasma T and DHT concentrations were significantly lower than those of the control days on a paired t test. No significant change in serum LH concentration could be demonstrated. Similar results were observed after 48, 72 and 96 hours of ACTH stimulation.     

Strategic approach of hyperandrogenism in women

Based on the results of the laboratory screening of 35 hirsute patients, a strategic approach of hyperandrogenism is proposed. The determination of plasma concentration of total testosterone (T), androstenedione (A) and dehydroepiandrosterone sulfate (DHEAS) appeared to be the basic investigation before to further explore the adrenal (ACTH test) and/or ovarian (gonadotropin measurements) androgen secretion. Together with the clinical findings, plasma T, A and DHEAS levels generally bring evidence of androgen-secreting tumors or polycystic ovaries, or suggest the possibility of adrenal hyperplasia. In the other cases, only the determination of plasma unbound T level is useful for demonstrating the hyperandrogenism. Finally in patients with 'so-called' idiopathic hirsutism, while evidence of excessive androgen production can be obtained by the laboratory screening, the origin of this hyperandrogenism remains uncertain in most cases.     

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.     

Activation of adrenal function in fetal sheep by the infusion of adrenocorticotropin to the fetus in utero

We determined whether ACTH1-24, infused into fetal lambs at a rate that is known to cause premature labor, elicits changes in the responsiveness of the fetal adrenal glands, and alters the pattern of corticosteroid output. Plasma cortisol (F), corticosterone (B) and progesterone (P4) were measured during 72 h of infusion of saline or ACTH (10 micrograms/h) beginning on Day 127 of pregnancy. Adrenals were then dispersed into isolated cells, and the output of F, B and P4 after exogenous ACTH determined in vitro. Plasma concentrations of F and B were higher in ACTH-treated fetuses. The increment in F (5-to 7-fold) was greater than that in B (2-fold) such that the F:B ratio in plasma of ACTH-treated fetuses on Days 2 and 3 of infusion was 2.5 times higher than in controls. After 72 h of infusion, the adrenal weights in ACTH-treated fetuses (741 +/- 38 mg, +/- SEM; n = 4) were greater than in the control animals (349 +/- 11 mg). There was a significant effect of ACTH pretreatment in vivo on F output by isolated adrenal cells in vitro. Mean increments in F output after addition of ACTH1-24 (5000 pg/ml) in vitro rose from 368 +/- 235 pg/50,000 cells in controls, to 64,639 +/- 19,875 pg/50,000 cells after ACTH in vivo. There was no significant effect of ACTH in vivo on B output in vitro; the ratio of F:B output, either in the absence or presence of ACTH in vitro, was significantly higher in cells from ACTH-pretreated fetuses. There was a significant effect of in vivo ACTH on in vitro P4 output. After ACTH treatment in vivo there was an increase in the vitro output ratio of F:P4, but no change in the output ratio of B:P4. We conclude that ACTH treatment of the fetal lamb in vivo results in activation of fetal adrenal function, increased fetal adrenal responsiveness to ACTH, and directed corticosteroid biosynthesis towards cortisol. Our results are consistent with an increase in fetal adrenal 17 alpha-hydroxylase activity after ACTH treatment.     

Salivary cortisol in low dose (1 microg) ACTH test in healthy women: comparison with serum cortisol

To date, a single report has appeared on the use of salivary cortisol for adrenal function testing with a low dose ACTH, although 1 microg has become preferred as a more physiological stimulus than the commonly used 250 microg ACTH test. Our present study was aimed to obtain physiological data on changes of free salivary cortisol after 1 microg ACTH stimulation. This approach was compared with the common method based on the changes of total serum cortisol. Intravenous, low-dose ACTH test was performed in 15 healthy women (aged 22-40 years) with normal body weight, not using hormonal contraceptives, in the follicular phase of the menstrual cycle. Blood and saliva for determination of cortisol were collected before ACTH administration and 30 and 60 min after ACTH administration. Basal concentration of salivary cortisol (mean +/- S.E.M., 15.9+/-1.96 nmol/l) increased after 1 microg ACTH to 29.1+/-2.01 nmol/l after 30 min, and to 27.4+/-2.15 nmol/l after 60 min. The differences between basal and stimulated values were highly significant (p<0.0001). The values of salivary cortisol displayed very little interindividual variability (p<0.04) in contrast to total serum cortisol values (p<0.0001) A comparison of areas under the curve (AUC) related to initial values indicated significantly higher AUC values for salivary cortisol than for total serum cortisol (1.89+/-0.88 vs. 1.22+/-0.19, p<0.01). Correlation analysis of serum and salivary cortisol levels showed a borderline relationship between basal levels (r=0.5183, p=0.0525); correlations after stimulation were not significant. Low-dose ACTH administration appeared as a sufficient stimulus for increasing salivary cortisol to a range considered as a normal adrenal functional reserve.     

The effect of spironolactone on genital skin 5 alpha-reductase activity

The effect of spironolactone (S) on genital skin 5 alpha-reductase activity (5 alpha-RA) of hirsute women (HW) in vivo as well as in normal genital skin in vitro was evaluated. Thirteen HW (Ferriman-Gallwey score of 23.3 +/- 2.8) received S 100 mg twice a day for a month. Twenty-three non-hirsute women were selected as controls for the assessment of genital skin 5 alpha-RA. S was added to incubations of genital skin from 9 additional controls in vitro in concentrations from 1.2 X 10(-8) to 10(-5) M. HW had significantly higher conversion ratios (CR) of T to DHT compared to controls (P less than 0.05). Post treatment values for the CR T to DHT were significantly lower than prior to S (17.5 +/- 1.7 and 8.05 +/- 1.2%, P less than 0.05) and the mass of DHT produced also decreased by 37 +/- 9% (P less than 0.05). The CR T to 3 alpha-diol decreased by 30 +/- 9% (P less than 0.05). In 11 of 13 women, a significant reduction of 5 alpha-RA was demonstrated while in 2 patients the activity remained unchanged. The maximum in vitro inhibitory effect of S on the CR T to DHT occurred with a concentration of 1.2 X 10(-5) M (P less than 0.01). In conclusion, S has a direct inhibitory effect on 5 alpha-RA. The beneficial effect of S treatment in HW may be related, in part, to this inhibition of 5 alpha-RA.     

Partial deficiency in 21-hydroxylase in certain forms of hirsutism

The ACTH test is important when hirsutism occurs in women with a slight 21-hydroxylase deficiency, and normal basal 17-OH Progesterone (17-OH-P/plasma levels). Extensive hormonal assays: LH, FSH, Prolactin, 17 beta-estradiol (E2), Estrone, 17OH-P, Androstenedione, Testosterone, Cortisol (C), Dehydroepiandrosterone-S (DEA-S) were carried out in 36 hirsute women. 13 of these presented hormone levels as found in polycystic ovary syndrome (PCOS), 6 women presented a slight 21-hydroxylase deficiency (increased plasma 17-OH-P and decreased C after ACTH test with significant, p less than 0.01, increase of 17-OH-P/C and 17 women presented idiopathic hirsutism (IH). The hormonal pattern, in the basal condition, is not different in IH or in slight 21-hydroxylase deficiency. The ACTH test is able to differentiate between IH and adrenal hirsutism.     

Dehydroepiandrosterone sulfate and other possible influencing factors that modulate sex hormone-binding globulin levels in the hirsute patient.

This study was designed to investigate the most important factors affecting serum concentrations of sex hormone-binding globulin (SHBG) in women with hirsutism. We compared endocrine profiles based on biochemical measurements of LH, FSH, oestradiol, testosterone (T), prolactin, 17-hydroxy-progesterone, dehydroepiandrosterone sulphate (DHEAS), SHBG, cortisol and insulin in the follicular phase in 32 healthy women and 52 patients. The study group was subdivided according to SHBG levels into Group A (low level) and Group B (high level). Significant differences between Groups A and B were found in DHEAS and T levels, but not in body mass index or insulinaemia. There was a relationship between DHEAS and SHBG levels (r = 0.51) and between T and SHBG (r = 0.31). We conclude that DHEAS may be a significant modulator of SHBG in the female hirsute patient, an observation seldom mentioned in previous reports.     

Androgen secretion in ectopic ACTH syndrome and in Cushing's disease: modifications before and after surgery.

The role of ACTH in the control of adrenal androgen secretion is known, although the possible existence of other regulatory factors has been also suggested. While some data concerning Cushing's disease have been reported, only few studies concerned androgen levels in ectopic ACTH secretion. The aim of this study was to evaluate serum DHEA-S, androstenedione (A) and testosterone (T) levels in 36 women with ACTH-dependent Cushing's syndrome (30 with Cushing's disease and 6 with ectopic ACTH secretion) before and after surgery. Two men with ectopic ACTH production were also studied. In 30 women with Cushing's disease serum DHEA-S (9.6 +/- 0.9 micromol/l), A (15.2 +/- 1.2 nmol/l) and T (4.1 +/- 0.5 nmol/l) were higher than in controls (p < 0.01): elevated DHEA-S, A and T values were found in 8, 18 and 17 cases, respectively. After adenomectomy in 15 apparently cured patients DHEA-S, A and T levels were low at 1 - 3 months and at 6 - 12 months after surgery. At 18 - 24 months, DHEA-S remained low in spite of cortisol normalisation. In ectopic Cushing's syndrome, A levels were significantly higher (23.1 +/- 4.9 nmol/l) than in Cushing's disease (p < 0.05), while no differences were found in DHEA-S and T levels. Two patients had elevated DHEA-S values, 3 women had high T levels and 7 of the 8 patients had very high A concentration that was lowered in 3 operated cases. In conclusion, the pattern of adrenal androgen secretion is rather different in patients with pituitary or with ectopic Cushing's syndrome. While the frequency of DHEA-S and T alterations is similar, androstenedione secretion is greatly increased in the latter condition. It is suggested that in ACTH-secreting non-pituitary tumours, the production of a POMC-derived peptide, although unidentified, may lead to preferentially stimulated androstenedione secretion, without affecting other enzymatic pathways.     

Effects of acute alcohol intoxication on pituitary-gonadal axis hormones, pituitary-adrenal axis hormones, beta-endorphin and prolactin in human adolescents of both sexes

Teenage drinking continues to be a major problem in industrialized countries, where almost 35% of alcohol drinkers are under 16 years old. In the present paper we studied the effects of acute alcohol intoxication (AAI) on the pituitary-gonadal (PG) axis hormones, and the possible contribution of pituitary-adrenal (PA) axis hormones, beta-endorphin (BEND), and prolactin (PRL) to the alcohol-induced dysfunction of PG axis hormones. Blood samples were drawn from adolescents that arrived at the emergency department with evident behavioral symptoms of drunkenness (AAI) or with nil consumption of alcohol (controls [C]). Our results demonstrated that AAI produces in adolescents a high increase in plasma PRL, ACTH, and cortisol (F), and a contradictory behavior of testosterone (T) according to gender: plasma T was increased in females and decreased in males. ACTH and PRL correlated positively with F, dehydroepiandrosterone-sulphate (DHEAS) and T in females, which suggests that PRL and ACTH could synergistically stimulate adrenal androgen production. In contrast, the decrease in T and increase in BEND in males suggests that AAI could have an inhibitory effect on testicular T, perhaps mediated by BEND. The hormones studied are involved in the development of secondary sexual characteristics and the growth axis during adolescence. The deleterious effects of alcohol abuse should be made known to adolescents and the appropriate authorities.     

Simultaneous radioimmunoassay of testosterone and dihydrotestosterone

A radioimmunoassay, which simultaneously measures both testosterone (T) and dihydrotestosterone (DHT) in the same serum sample, is presented. Celite column chromatography is employed to separate T from DHT, and these two steroids from other potentially cross-reacting and interfering steroids. The normal values for men, women in the follicular phase, women in the luteal phase, ovariectomized and adrenal ectomized women, post-menopausal women and ovariectomized women for T are 5, 140 ± 1190 pg/ml, 307 ± 97 pg/ml, 285 ± 46 pg/ml, undetectable (<5 pg/ml), 262 ±47 pg/ml and 199 ±44 pg/ml; and for DHT 470 ± 165 pg/ml, 160 ±45 pg/ml, 147 ±44 pg/ml, undetectable (<5 pg/ml), 168 ± 27 pg/ml, 94 ± 15 pg/ml. The maximum sensitivity of the method was 10 pg/ml for T and 14.3 pg/ml for DHT when 1 ml was extracted. The blank in most assays was undetectable, but rarely exceeded 10 pg.     

Increased adrenal steroid secretion in response to CRF in women with hypothalamic amenorrhea

OBJECTIVE: To evaluate adrenal steroid hormone secretion in response to corticotropin-releasing factor (CRF) or to adrenocorticotropin hormone in women with hypothalamic amenorrhea. DESIGN: Controlled clinical study. SETTING: Department of Reproductive Medicine and Child Development, Section of Gynecology and Obstetrics, University of Pisa, Italy. PATIENT(S): Fifteen women with hypothalamic amenorrhea were enrolled in the study. Eight normal cycling women were used as control group. INTERVENTION(S): Blood samples were collected before and after an injection of ovine CRF (0.1 microg/kg iv bolus) or after synthetic ACTH (0.25 mg iv). MAIN OUTCOME MEASURE(S): Plasma levels of ACTH, 17-hydroxypregnenolone (17OHPe), progesterone (P), dehydroepiandrosterone (DHEA), 17-hydroxyprogesterone (17OHP), cortisol (F), 11-deoxycortisol (S) and androstenedione (A). RESULT(S): Basal plasma concentrations of ACTH, cortisol, 11-deoxycortisol, DHEA and 17OHPe were significantly higher in patients than in controls, whereas plasma levels of progesterone and 17-OHP were significantly lower in patients than in controls. In amenorrheic women the ratio of 17-OHPe/DHEA, of 17-OHPe/17-OHP and of 11-deoxycortisol/cortisol were significantly higher than in controls, while a significant reduction in the ratio of 17-OHP/androstenedione, of 17-OHP/11-deoxycortisol was obtained. In response to corticotropin-releasing factor test, plasma levels of ACTH, cortisol, 17-OHP, 11-deoxycortisol, DHEA and androstenedione were significantly lower in patients than in controls. In response to adrenocorticotropin hormone, plasma levels of 17-OHP, androstenedione and androstenedione/cortisol were significantly higher in patients than in controls. CONCLUSIONS: Patients suffering for hypothalamic amenorrhea showed an increased activation of hypothalamus-pituitary-adrenal (HPA) axis, as shown by the higher basal levels and by augmented adrenal hormone response to corticotropin-releasing factor administration. These data suggest a possible derangement of adrenal androgen enzymatic pathway.     

Late-onset adrenal hyperplasia in north Indian hirsute women

The occurrence of late-onset congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency was studied in 60 consecutive hirsute women by means of adrenocorticotrophin (ACTH)-stimulated serum 17-hydroxyprogesterone (17-OHP) levels. Five (8.3%) women had an exaggerated response (ACTH-stimulated 17-OHP 3,160 +/- 560 ng/dl). All of them had regular periods and 3 were virilized. The other 2 were indistinguishable from those with idiopathic hirsutism or polycystic ovarian disease.     

Precursors of plasma androstanediol- and androgen-glucuronides in women

Although androstanediol (AD) and androstanediolglucuronide (ADG) are generally considered to be parameters of peripheral androgen action, their plasma levels do not always vary in parallel, suggesting that they may have different precursors. Few hard data being available concerning ADG precursors in women, we studied in postmenopausal women with absent or suppressed adrenal function, the blood conversion rates of testosterone (T), dihydrotestosterone (DHT), androstenedione (A) and dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) to AD and ADG respectively, as well as the conversion of AD to ADG. Moreover conversions of these precursors to testosteroneglucuronide (TG) and dihydrotestosteroneglucuronide (DHTG), respectively, were also studied. Our data show that, whereas plasma A and DHT are the major precursors of AD, plasma DHEAS and A are the major precursors of plasma ADG, accounting for 50 and 15%, respectively, of plasma ADG, A being the major precursor of plasma TG and DHTG, respectively. When the conversion rates, obtained in this study, were applied to the plasma concentration of precursors found in normal young and postmenopausal women, respectively, the calculated concentration of product steroids accounted for almost the totality of the actual plasma levels of ADG, TG and DHTG respectively. The difference in relative importance of their precursors, explains that plasma concentrations of AD and ADG do not always vary in parallel; moreover, the importance of DHEAS as precursor of ADG explains the suppression by dexamethasone and the increase after adrenocortical stimulation of plasma ADG levels.     

A comparison of the effects of castration and 6-methylene progesterone, a 5 alpha-reductase inhibitor, on the rat ventral prostate

6-Methylene progesterone (6MP) is an irreversible in vitro kcat inhibitor of rat prostate 5 alpha-reductase, the enzyme which converts testosterone (T) to dihydrotestosterone (DHT). Treatment of adult rats with 6MP or diethylstilbestrol (DES) decreased the weight of the ventral prostate (VP) by 45%, while castration reduced it by 86%. Histologically, the 6MP-treated VP were indistinguishable from those of controls, while the VP from DES-treated rats showed fibrous stromal hypertrophy as in castrated rats. The prostatic hydroxyproline content, an index of collagen levels, was enhanced by castration or DES, but was not significantly increased by 6MP. Within 2 days of 6MP treatment, the 5 alpha-reductase activity was reduced by 46% and ornithine decarboxylase (ODC) activity was lowered by 27%. During this time the prostatic acid phosphatase activity increased 42% and remained elevated with continued exposure to 6MP up to 13 days. The castration-induced involution of the VP was accompanied by a reduction in serum T and an increase in serum luteinizing hormone (LH). 6MP had no effect on T and LH serum levels but reduced the DHT content within the VP by 64%. Our results indicate that the structure and secretory acid phosphatase activity of the VP are less sensitive to changes in the ratio of T:DHT than is cell proliferation. Thus, the relative amounts of DHT and T within the VP may prove to be more significant than the absolute amount of either androgen in controlling prostate growth or its attendant neoplasms.     

Responsiveness of cortisol and dehydroepiandrosterone to ACTH in children

In a total of 101 children, the dehydroepiandrosterone (DHA) and cortisol (F) levels were measured before and after ACTH (Synacten) administration. F responsiveness was unchanged during development, while DHA responsiveness in healthy children was highest during adrenarche. In hypopituitary patients DHA levels were lower than in the controls, but responsiveness to ACTH showed similar changes during development. Children with Turner's syndrome and hypergonadotrophic males had the response in elevated DHA levels while ACTH-induced DHA response related to bone-age matched controls. We conclude that regulation of adrenal androgens is mediated by both ACTH and another hypothalamo-pituitary hormone, perhaps independent of gonadal activation, but requiring gonadal integrity.     

Sexual incentive motivation in male rats requires both androgens and estrogens

In Experiment 1 castrated male rats were implanted with a Silastic capsule containing either E or cholesterol (CHOL) 35 days after castration. They were then tested for sexual incentive motivation and copulatory behaviors every 5th day for 3 weeks. None of the treatments affected sexual incentive motivation. After the last test, all subjects were implanted with DHT-containing Silastic capsules, and tests continued for another 3 weeks. While E + DHT enhanced sexual incentive motivation and copulatory behavior, DHT alone failed to do so. In Experiment 2 the aromatase inhibitor fadrozole (F) was combined with testosterone (T). T restored all behaviors to the level seen in intact rats, and F significantly reduced these effects. In fact, T + F was not different from DHT. T and DHT restored the weight of the prostate and seminal vesicles to levels close to those of intact rats. In Experiment 3 a lower dose of E was employed. Also this dose of E failed to affect sexual incentive motivation while E + DHT restored it to the level of intact animals. Castration enhanced the serum concentrations of LH and FSH. E alone caused a marked reduction, and E + DHT brought both gonadotropins back to the level of intact animals. It was concluded that the doses of E and DHT employed in these experiments were within or close to the physiological range, and that such doses of E completely fail to enhance sexual incentive motivation in castrated animals. DHT has small or no effects. It appears that sexual incentive motivation and copulation require simultaneous stimulation of androgen and estrogen receptors.     

Radioimmunoassay of 17β-hydroxy-5α-androstan-3-one, 4-androstene-3,17-dione,dehydroepiandrosterone, 17-hydroxyprogesterone and progesterone and its application to human male plasma

RIA methods for the measurement of 5α-dihydrotestosterone (DHT), androstenedione (Δ4), dehydro-epiandrosterone (DHEA), 17-hydroxyprogesterone (17-OHP) and progesterone (P) have been developed and applied to the study of factors determining the levels of these steroids in males.It has been shown that DHT, 17-OHP and DHEA levels are lower in elderly males than in young (<50 years) subjects, Δ4 and P levels remaining constant. All steroids, with the exception of DHT, show significant nyctohemeral variations: upon ACTH stimulation T levels decrease, whereas Δ4 and DHEA, 17-OHP and P increase significantly. Dexamethasone has the reverse effect, although T levels do not decrease. HCG stimulation results in a significant increase of T, DHT, 17-OHP and Δ4 levels, whereas DHEA and P levels are hardly influenced. In a small group of orchidectomized males, all steroids studied, with the exception of P were significantly lower than in normal males of similar age.It is concluded that in males T, DHT and 17-OHP have an almost exclusive testicular origin; Δ4 has a mixed testicular and adrenal origin, whereas DHEA has a predominant and P an exclusive adrenal origin in males.