ENDOCRINE EFFECTS OF VASECTOMY

Abstract

In order to provide information on the endocrine effects of vasectomy, unconjugated pregnenolone, dehydroepiandrosterone, androstenedione, testosterone, dihydrotestosterone, oestrone and oestradiol were analysed in the blood plasma of twenty Mexican men on two occasions before and 1, 3, 6 and 12 months after vasectomy. Vasectomy appeared to be associated with a significant decrease in the plasma levels of pregnenolone, dehydroepiandrosterone and androstenedione and a significant increase in the levels of dihydrotostrone and oestrone. A probably significant increase in oestradiol levels took place 12 months after vasectomy but not before. No consistent changes were found in testosterone (up to 12 months) or in FSH and LH levels (up to 6 months) after vasectomy. The unconjugated steroids indicated above, except oestrone, were also estimated, whenever possible, in seminal plasma specimens obtained from thirty-nine subjects (including the twenty indicated above) on the same occasions. Vasectomy was associated with a highly significant decrease of seminal plasma dihydrotestosterone levels on all occassions and a significant decrease in androstenedione levels after 6 and 12 months. After 12 months there was a decrease in dehydroepiandro-sterone and an increase in oestradiol; these changes were both probably significant. In another preliminary study, the levels of pregnenolone sulphate, dehydroepiandrosterone sulphate, testosterone glucuronide, testosterone sulphate and dihydrotestosterone sulphate were estimated before and 1 month after vasectomy in the seminal plasma of fourteen to seventeen subjects. Testosterone glucuronide fell, probably significantly, but other conjugates were unchanged. The data indicate that vasectomy may be associated with significant changes in the circulating and in seminal plasma levels of several steroids. The gradual nature of some of the changes observed suggests the necessity of conducting in several centres large-scale, long-term studies on vasectomized subjects and on a carefully matched control group.