An enzymatic defect in androgen biosynthesis in human testis: a case report and response to therapy

Intratesticular and plasma steroid profiles in fertile and infertile men

In 24 apparently healthy men who requested sterilization by vasectomy, we have measured the intratesticular and peripheral plasma levels of 9 unconjugated and 5 sulphoconjugated steroids. These steroid levels were then compared with those found in a group of 18 men, admitted to the hospital with complaints of infertility. With the exception of higher dihydrotestosterone levels in the infertile group, no differences were found between the two groups with regard to the peripheral plasma levels of the unconjugated or sulphoconjugated steroids studied. On the other hand, the intratesticular levels of cortisol, pregnenolone, androstenedione, dihydrotestosterone, pregnenolone sulphate and testosterone sulphate (but not those of testosterone) were significantly diminished in the infertile group. With the exception of dehydroepiandrosterone levels in the fertile group, and dehydroepiandrosterone sulphate and dihydrotestosterone sulphate in the infertile group, the intratesticular steroid levels were uncorrelated with the plasma levels. The data are interpreted as suggesting that a) male infertility may be associated with intratesticular alterations of steroid metabolism which are not reflected by the peripheral steroid levels; b) the plasma and intratesticular levels of testosterone are not sensitive enough indices for the endocrine evaluation of male infertility; c) the role of the sulphoconjugated forms of steroids in the maintenance of male fertility deserves further investigation.

In vitro steroid metabolic studies in human testes I: Effects of estrogen on progesterone metabolism

A technique of incubation of testicular tissue in vitro with radiolabeled precursors was applied in the investigation of the steroid biosynthesis by testes of four young men after long-term, high-dose estrogen treatment. A positive correlation between plasma and testicular steroid levels, and in vitro capacity of the testes to metabolize progesterone was demonstrated. Estrogen administration produced a very significant inhibition of plasma and testicular levels of testosterone. The in vitro synthesis of testosterone from progesterone was very severely impaired; especially 17alpha-hydroxylation of progesterone. 20alpha-hydroxysteroid-dehydrogenase activity was found to be increased after estrogen treatment, both in vivo and in vitro. These findings suggest that testicular 17alpha-hydroxylase activity (and possibly also 17-20 lyase activity) is either under gonadotropin regulation, or is directly suppressed by estrogen. This could result by decreased enzyme synthesis, direct enzyme inhibition or affectation of the cofactors or cytochromes necessary for the enzymatic activity. 20alpha-reduction of C21-steroids would represent an alternative pathway for their catabolism, not regulated by gonadotropin or not affected by estrogen, that would be significant in situations with reduced 17alpha-hydroxylase activity.