Pituitary gonadal function in diabetic male patients with and without impotence

Assessment of pituitary function was undertaken in diabetic male patients with and without impotence, and in normal subjects, using a combined gonadotropin releasing hormone (GnRH) and thyrotropin releasing hormone (TRH) test. Basal plasma levels of testosterone, gonadotropins, PRL and TSH were similar in the diabetic patients and controls. Following the administration of I.V. GnRH 150 microgram and TRH 500 microgram, diabetic patients with impotence demonstrated a lower LH response at 30 and 150 minutes and an increased PRL response at 20 minutes, which was statistically significant when compared to controls. FSH and TSH were similar in the diabetic patients and controls. The GnRH and TRH test was repeated in impotent diabetic patients while receiving 0.8-1 mU/kg/hr of insulin through an infusion pump. No difference in LH and PRL response could be demonstrated. These results demonstrate that following GnRH and TRH test, diabetic patients with impotence have a significantly different LH and PRL response than controls. In these patients acute control of hyperglycemia using an insulin infusion pump did not reverse the abnormal response.