Pituitary-testicular axis in diabetic men with and without sexual impotence.

In nine impotent diabetics (ID), eight diabetics with normal sexual function (ND), eight impotent non diabetics (IN) and seven normal patients (NN), we found normal basal FSH and LH levels. Plasma testosterone (T) values were significantly lower in ID and IN in comparison with NN and ND. After LHRH injection, plasma T increased in ID up to normal values. In non diabetic patients (NN and IN), LHRH induced a slight but significant rise in blood glucose. Post LHRH gonadotropins response was in the normal range for all groups and the amplitude of the response was highly correlated with basal levels except for LH in ND. Mean blood glucose during the test and LH response to LHRH were not inversely correlated in the patients studied. We conclude that impotence in diabetic patients is a neurological complication and that low testosterone levels are probably secondary to a decreased coital frequency. ID and IN probably share a common pattern of inadequate hypothalamic feedback control in the presence of low testosterone levels.