Hyperprolactinaemia among infertile patients and its effect on sperm functions.

The effects of hyperprolactinaemia on sperm function were investigated in 264 men with oligozoo-, asthenozoo-, or teratozoospermia and who were attending a male infertility clinic. None of the patients exhibited galactorrhea or complained of impotence. There was no correlation between abnormal values in spermiogram and hyperprolactinaemia. After multiple measurements of serum prolactin concentration, 15 cases (5.7%) were diagnosed as hyperprolactinaemic (> or = 10 ng ml-1). Six of these patients were taking cimetidine and six were taking anti-anxiety drugs. Serum prolactin returned to the normal level after discontinuation of these drugs; thus these 12 cases were considered as drug-induced hyperprolactinaemia. The other three patients were diagnosed as having pituitary microadenomas and received bromocriptine treatment; the serum prolactin levels normalized within 1 month. No changes in sperm concentration, motility or morphology were found after normalization of serum prolactin levels. Sperm fertilizing ability was monitored by the hamster test for 10 months in the three patients with pituitary microadenoma, and no improvement was observed. Results suggest that hyperprolactinaemia, which does not cause symptoms, has little effect on the impairment of sperm functions. Measurement of serum prolactin in infertile men could be justified, however, for early detection of pituitary adenomas.