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.