CONTRIBUTION OF DIHYDROTESTOSTERONE TO MALE SEXUAL-BEHAVIOR

Objective-To document the relative importance of endogenous sex steroids in modulating the frequency of orgasms, the dominant aspect of sexual behaviour in healthy eugonadal men. Design-Measurement of adrenal and testicular sex steroids in a sample of army recruits and study of their relation to frequency of orgasms ascertained by questionnaire after potential confounding variables were controlled for. Setting-Military campus and military hospital laboratories in Athens, Greece. Subjects-92 consecutively enrolled healthy male recruits aged 18-22 years. Main outcome measures-Weekly number of orgasms. Serum concentrations of testosterone, dehydroepiandrosterone sulphate, dihydrotestosterone, oestradiol, oestrone, Delta-4-androstenedione, and sex hormone binding globulin. Results-Serum dihydrotestosterone concentration was the only independent hormonal predictor of the frequency of orgasms; an increase in concentration of 1.36 nmol/l (about 2 SD) corresponded to an average increase of one orgasm a week. Conclusions-Differences in concentrations of circulating dihydrotestosterone within the normal range may represent a major predictor of sexual activity in healthy young men.