The gonadotropin response of men with varicoceles to a four-hour infusion of gonadotropin-releasing hormone.

The serum gonadotropin, testosterone, and estradiol responses to a 4-hour intravenous infusion of gonadotropin-releasing hormone (GnRH) were studied in four groups of men: severely oligospermic men with varicoceles and sperm densities less than 1 X 10(7)/ml, men with varicoceles and sperm densities between 1.1 X 10(7) and 3 X 10(7)/ml, men with varicoceles and sperm densities greater than 3 X 10(7)/ml, and men of normal fertility. Each group had similar preinfusion luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, and estradiol levels. Both the severely oligospermic men and the men with sperm densities between 1.1 X 10(7)/ml and 3 X 10(7)/ml had excessive gonadotropin responses to the GnRH infusion. The gonadotropin responses of the men with sperm densities greater than 3 X 10(7)/ml were not different from normal. These results demonstrate that men with varicoceles and sperm densities less than 3 X 10(7)/ml have an altered integrity of their hypothalamic-pituitary-testicular axes, which can be demonstrated by their responses to GnRH.