Prolactin and impotence in diabetes mellitus.

A study was undertake to determine whether impotence in some diabetic patients might be due to a coincidental prolactinoma and therefore be potentially treatable. Of 83 consecutive men attending a diabetic clinic, three were found to have persistent mile to moderate hyperprolactinaemia. None of the three was impotent or taking any drug know to be associated with elevated serum prolactin, and anterior pituitary responses and pituitary fossa tomograms did not reveal any abnormality. The mean serum prolactin concentration of the 37 insulin-treated men was not significantly different from that of the 46 men on diet with or without anti-diabetic tablets, nor was there any significant difference between the mean serum prolactin concentrations of the 19 impotent men and of the 64 non-impotent men.