Plasma testosterone response to HCG in normal men without and after administration of anabolic drug

In young, adult male volunteers Leydig cell function tests were performed consisting of i.m. administration of 1500, 3000 or 4500 IU of HCG on days 1, 2 and 3 and plasma testosterone determination by radioimmunoassay. The stimulatory effect of HCG known from the literature is reconfirmed. However, no difference between the effect of the three dosage levels was found and the first significant effect of HCG was observed 24 h after its first application. Testosterone levels on day 3 and 4 are higher but not different from each other. A depression of plasma testosterone after treatment with an anabolic steroid (1alpha, 17alpha-dimethyl-5alpha-androstan-17-ol-3-one) 20 mg daily for 14 days is described. Reactivity to HCG was sustained in these subjects, but testosterone response to HCG was diminished at all investigated time intervals.