Blood production rate of dihydrotestosterone in the syndrome of male pseudohermaphroditism with testicular feminization

Androgen insensitivity syndrome

Over the past four years, major advances in the understanding of the aetiology and pathogenesis of the androgen insensitivity syndrome (AIS) have occurred. This review aims to summarize current information on clinical, diagnostic, therapeutic and molecular aspects of AIS.

Pharmacokinetics and pharmacodynamics of FK143, a nonsteroidal inhibitor of steroid 5 alpha-reductase, in healthy volunteers

The pharmacokinetics and pharmacodynamics of FK143, a new nonsteroidal inhibitor of steroid 5 alpha-reductase, were investigated in healthy volunteers, with use of plasma FK143 concentrations and serum dihydrotestosterone levels as an index for pharmacologic effects. The area under the plasma concentration-time curve from zero to infinity [AUC(0-infinity)] and maximum plasma concentration [Cmax] were increased dose proportionally after oral administration (100 to 500 mg) while subjects were in the fed state. The AUC(0-infinity) and Cmax after 500 mg oral administration during fed conditions were significantly larger than those during the fasted state, suggesting an increase of the absorption of FK143. Dihydrotestosterone concentrations after a single administration of FK143 (100 to 500 mg) during fed conditions decreased to about 65% of predose values and thereafter slowly recovered to the same levels as predose values at 168 hours. A combined pharmacokinetic-pharmacodynamic model was constructed with use of changes in dihydrotestosterone concentrations. The pharmacokinetic-pharmacodynamic profiles of FK143 after repeated administration were predictable with use of the pharmacokinetic-pharmacodynamic parameters obtained after a single administration of FK143.

Incomplete testicular feminization syndrome: studies of 17 beta-oestradiol-binding activity and aromatase activity in cultured genital fibroblasts showing impaired dihydrotestosterone-binding

Dihydrotestosterone (DHT) and 17 beta-oestradiol binding, and aromatase activity were measured in cultured genital skin fibroblasts from two siblings with the incomplete testicular feminization syndrome. Whole-cell and nuclear DHT binding in the cells from both patients were reduced to 80% and 60%, respectively of those in a normal male subject. The nuclear oestradiol binding was not impaired in the fibroblasts from the patients whose plasma oestradiol was normal or a little elevated. Although gonadectomy led to a decrease in plasma testosterone concentration, the concentration of testosterone-binding globulin showed no change suggesting no apparent effect on testosterone-binding globulin synthesis by testicular steroids. There was no significant difference in aromatase activity of the fibroblasts between the patients and the normal male subjects. The relatively increased oestrogen concentration in the syndrome might result from oestrogen production in testes, but is unlikely to be from peripheral tissues such as fibroblasts. This is the first report to examine oestradiol binding and aromatase activity in the cells from the incomplete testicular feminization associated with impaired DHT binding. These findings may give new insight into the pathogenesis of abnormal male sexual differentiation in the patients with testicular feminization syndrome.

Failure of the müllerian regression factor in two patients with complete androgen insensitivity syndrome

The present paper describes the histological and endocrinologic features of 2 subjects with 46,XY karyotype affected by complete androgen insensitivity syndrome (AIS) with müllerian structures. Both patients had fallopian tubes, but only one had also uterus and presented a seminoma. Serum levels of luteinizing hormone, testosterone and estradiol were high or in the upper part of normal limits, whereas levels of follicle-stimulating hormone were normal. The association between AIS and the presence of müllerian structures observed in these 2 patients might be explained by an impaired synthesis of müllerian regression factor or by a failure in its mechanism of action.

Treatment of hirsutism with spironolactone

The discovery of compounds possessing antiandrogenic activities has led to their utilization in the treatment of hirsutism of various aetiologies. Spironolactone generally lowers the plasma testosterone by altering its formation and metabolism as well as by decreasing its blood production rate; the medication also contributes to increase the peripheral conversion of testosterone to oestradiol. A major action is that spironolactone inhibits androgen binding to receptor molecules in the cytosol or the nucleus of target tissues such as the skin. During the last five years, we have studied over 450 cases of hirsutism. Approximately 80% of these women were treated with spironolactone alone or in association with dexamethasone (2.5%) or an oral contraceptive (15%). Hirsutism was classified according to Lorenzo (1970). Good to very good clinical results were observed in 80% of the patients who were under study for a minimum of 3 to 4 years. Adverse side-effects were recorded in less than 5% of our group of patients. On the basis of our data and our clinical experience, we conclude that spironolactone is an effective drug in the treatment of female hirsutism.

The dynamics of 11-beta-hydroxy-androstenedione (11 OHAD) metabolism in man

The aim of the study was to determine the main metabolic parameters of 11-beta-hydroxy-androstenedione (11 OHAD) in man. Seven normal subjects were investigated at 1-3 months interval by 2 types of isotope dilution techniques using a tritiated tracer: constant infusion and bolus iv injection. 3H-11 OHAD and 3H-11-beta-hydroxy-androsterone (3H-11 OA) were isolated by gel column chromatography, unlabeled 11 OHAD was determined by RIA, unlabelled 11 OA by GLC. The results included computation of free and conjugated catabolite fractions. 3H-11 OHAD MCR determined from the infusion or the injection data averaged ca 1250 ml/min or 1800 L/d (CV: +/- 10%) providing a mean estimation of unlabelled 11 OHAD BPR of 1.5 +/- 0.15 mg/d. UPR estimations gave similar values. 3H-11 OHAD fractional catabolic rate drawn from the postinfusion or the injection curve averaged ca 1.4% per min (CV: +/- 7%). Mean total distribution volume ranged between 90 and 120 L according to the type of experiment. Extrapolation to time zero of the injection curve (2 exponentials) provided an estimation of 32 +/- 5 L for rapid exchange compartment. Urinary recovery of labelled compounds was complete within 24 h whereas the excretion of undegraded 3H-11 OHAD was undetectable; urinary clearance rate of 3H-conjugates approached that of creatinine. The present data show that: the secretion rate of 11 OHAD is equivalent to that of its direct precursor, adrenal androstenedione; its large MCR value results from the size of its exchange volume-equivalents.(ABSTRACT TRUNCATED AT 250 WORDS)

Age-related changes of plasma steroids in normal adult males

Plasma cortisol, 17-hydroxyprogesterone (17-OH-P), testosterone (T), 5 alpha-dihydrotestosterone (DHT, estrone (E1) and estradiol (E2), were measured in 94 normal adult men aged between 20-99, using RIA methods after chromatographic separation of steroids on Sephadex LH-20 columns. All plasma steroids except 17-OH-P, were age dependent: cortisol, testosterone and DHT decreased significantly with age, whereas estrone and estradiol were significantly increased in elderly men. Cortisol, testosterone, T/DHT ratio and estradiol levels were significantly correlated with age. The age related changes of plasma steroids in elderly men, were suggestive of decreased cortisol secretion, and decreased testicular function with increased peripheral conversion of androgens into estrogens. Testosterone was positively correlated with its precursor (17-OH-P) and respectively its peripheral metabolites (DHT and E2). The negative correlation between estrone and 17-OH-P found in elderly men, suggested that increased estrogen level in aging males may be considered able to inhibit the testicular androgen production.

The pathogenesis of benign prostatic hyperplasia

Development of prostatic hyperplasia is an almost universal feature of the aging man and dog, and in both species the process develops only in males with intact testes. As the result of studies of plasma hormone levels as a function of age, measurements of the concentration of androgen and of androgen receptor proteins within the prostate, and studies of the effects of the administration of various hormones on growth of the prostate in the castrated dog, it is possible to provide a working hypothesis as to the pathogenesis. Dihydrotestosterone accumulation within the gland serves as the hormonal mediator for the hyperplasia in both species; the accumulation probably occurs in part because of decreased catabolism of the molecule and in part because of enhanced intracellular binding of the molecule. The process is accelerated by estrogen, which enhances the level of the androgen receptor in the gland; increase in the androgen receptor allows for androgen-mediated growth even in the face of declining androgen production in advanced age. On theoretic grounds the therapeutic implications of this model are exciting; several potential medical treatments may be feasible that do not involve a chemical castration.

New therapeutic approach to the hirsute patient

Spironolactone, an aldosterone antagonist currently used in the treatment of hypertension, has numerous antiandrogenic side effects. Decreased production rates of testosterone in intact (N = 10) and hirsute (N = 6) women, respectively, were noted after short (7 days) or long-term (6 months) administration of the drug, 25 mg twice daily. A 50% diminution in the urinary 17-ketosteroid excretion was also observed after 6 months of therapy. Assessment of the treatment was done by the patients: a reduction in hair growth rate was initially observed after 3 to 4 months, followed by the appearance of a more downy type of new growth and a decrease in diameter of the hair shaft. It is concluded that this beneficial effect is obtained by a decrease in the testosterone production rate and probably through competitive inhibition of spironolactone and/or canrenone with the androgen receptor in human hair follicles.

Klinefelter's syndrome: a study of its hormonal plasma pattern

Plasma testosterone (T), dihydrotestosterone (DHT), 17 beta-estradiol (E2), 17-hydroxyprogesterone (17-OHP), androstenedione (delta), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulphate (DHEAS), 5-androstene-3 beta-17 beta-diol (A-diol) and cortisol (F) have been measured in a group of normal males and in a group of patients with Klinefelter's syndrome (KS) before and after hCG stimulation. Significantly lower baseline levels of T and DHT and significantly higher baseline levels of E2 were found in patients with KS. No significant differences were found between baseline levels of 17-OHP, delta, DHEA, DHEAS, A-diol, and F. After hCG stimulation between T, DHT, E2 and 17-OHP levels showed a significant increase in the two groups of subjects. The percentage variation of T and DHT, however, was much less important in Klinefeiter patients, while E2 and 17-OHP did not show a significantly different pattern from that of normal controls, hCG administration did not produce any significant variation of delta, DHEA, DHEAS, and F in the two groups of subjects, while A-diol levels increased significantly in normal subjects, but not in Klinefelter patients. Our data may be consistent with the hypothesis that testicular steroidogenesis in Klinefelter patients is impaired below the 21-C-steriod level not only at delta 4 but also at the delta 5 pathway.

Male pseudohermaphroditism with gynaecomastia due to testicular 17-ketosteroid reductase deficiency

A 28-year-old male pseudohermaphrodite with gynaecomastia was raised as a female until the age of 17 years, at which time he developed masculine features (deepening of the voice, development of facial hair, male distribution of body hair and male body habitus) and assumed a male gender role. He had a small phallus with perineal urethra, absence of labioscrotal fusion, presence of vaginal pouch and undescended testes. The testicular biopsy showed hyalinization of the tubular basement membrane, lack of spermatogenesis and hyperplastic Leydig cells. Baseline peripheral plasma studies showed androstenedione concentrations ten times normal, low testosterone, elevated oestrone and elevated gonadotrophins. The in vitro incubation of testicular tissue showed no significant conversion of androstenedione to testosterone. However, two types of peripheral tissues, skin fibroblasts and erythrocytes, had a normal conversion, as did the body overall as measured by the technique of androstenedione constant infusion. These studies demonstrate that the 17-ketosteroid reductase deficiency of the patient was limited to the testes.

Serum dihydrotestosterone in patients with benign prostatic hypertrophy

Serum dihydrotestosterone (DHT) and testosterone were measured by radioimmunoassay in 24 normal men aged 60 to 80 years and in 25 patients with benign prostatic hypertrophy in the same age range. There was a significant increase in the level of dihydrotestosterone in patients with prostatic hypertrophy but no significant difference was found between the testosterone levels of the 2 groups. The scatter of the individual values for DHT indicated that this measurement has little practical clinical application in the diagnosis of prostatic hypertrophy. It is suggested that the increase in DHT may be due, at least in part, to a prostatic contribution to the circulating level and the relevance of this observation in relation to the aetiology of benign prostatic hypertrophy is discussed.

Partial androgen insensitivity: the Reifenstein syndrome revisited

We investigated eight patients with the Reifenstein syndrome to define the hormonal basis for this condition. The patients had normal or elevated concentrations of plasma androgens, normal production rates of testosterone and dihydrotestosterone, elevated serum levels of luteinizing hormone and normal 5alpha-reductase activity in skin fibroblasts. These findings indicate that the syndrome results from defective androgen action rather than from decreased androgen synthesis. The term "partial androgen insensitivity syndrome" describes this condition more accurately than a term based on clinical phenotype. Dihydrotestosterone binding studies in skin fibroblasts demonstrated two genetic variants similar to those reported in complete androgen insensitivity syndrome. One patient had a partial deficiency of cytoplasmic dihydrotestosterone binding, and four others had normal binding activity. The cause of the androgen insensitivity in the last four cases is unknown. Treatment with testosterone suppressed serum luteinizing hormone levels and promoted mild virilizing effects.

Male pseudohermaphroditism due to steroid 5-alpha-reductase deficiency

A new inherited form of male pseudohermaphroditism has been investigated in a pedigree of 24 families with 38 affected males. At birth, the affected males (46 XY) have a clitoral-like phallus, bifid scrotum and urogenital sinus. The testes are in the inguinal canals or labial-scrotal folds. The Wolffian structures are normally differentiated; there are no Mullerian structures. At puberty a muscular male habitus develops with growth of the phallus and scrotum, voice change and no gynecomastia. The subjects have erections, ejaculations and a libido directed towards females. They have decreased body hair, a scant to absent beard, no temporal hair line recession and a small prostate. Testicular biopsy reveals a normal testis. The mean plasma T levels in affected adults are significantly higher, and the mean plasma DHT levels are significantly lower when compared to those in normal subjects. The plasma T:DHT ratios range from 35 to 84 compared to 8 to 16 in normal subjects. After the administration of hCG, the T:DHT ratios in affected male children range from 74 to 162 compared to 3 to 26 in the control subjects. In affected adults, mean plasma LH and FSH levels are significantly higher than in normal subjects. In the affected subjects, the metabolic clearance rates of T and DHT are normal, but the conversion ratio of T to DHT is less than 1 per cent. The endogenous mean urinary E:A and E-OH:A-OH ratios, and the urinary E:A and E-OH:A-OH ratios after the infusion of radioactive T are significantly higher than in normal males. Inheritance is autosomal recessive with some sibling sisters showing the same biochemical defect, and obligate carrier parents showing an intermediate defect. These data support our thesis that the defect in these male pseudohermaphrodites is secondary to decreased steroid delta 4-5 alpha-reductase activity. The affected subjects provide a clinical model for delineating the roles of T and DHT in sexual differentiation and development. This entity also demonstrates an inherited disorder of steroid metabolism in which the basic enzyme deficiency resides in the target tissues.