A SIMPLE HCG STIMULATION TEST FOR NORMAL AND HYPOGONADAL MALES

A simple human chorionic gonadotropin (hCG) test to measure Leydig cell function is described. Plasma testosterone was measured on 2 occasions, once before i.m. injection of 10,000 IU hCG and again 4 days later. Preliminary tests in 10 adult males showed a maximal increase in plasma testosterone between the 3rd and 5th day that was confirmed in a further 20 normal subjects when measured once on the 4th day. Except for 2 patients with hypospermatogenesis, 24 showed a good response and the mean increase was comparable with that in normal males. Nineteen patients with Klinefelter''s syndrome usually had lower basal levels and showed a poor response, with the exception of 6 patients in whom there were moderate but definite increases. Twelve patients with hypogonadotropic hypogonadism had basal testosterone concentrations below 1 ng/ml, and 8 responded poorly to hCG stimulation. Four patients showed a moderate but definite response.