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 1×107/ml, men with varicoceles and sperm densities between 1.1×107 and 3×107/ml, men with varicoceles and sperm densities greater than 3×107/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 1.1×107/ml and 3×107/ml had excessive gonadotropin responses to the GnRH infusion. The gonadotropin responses of the men with sperm densities greater than 3×107/ml were not different from normal. These results demonstrate that men with varicoceles and sperm densities less than 3×107/ml have an altered integrity of their hypothalamic-pituitary-testicular axes, which can be demonstrated by their responses to GnRH.