Influence of chronic hyperprolactinemia induced by sulpiride on the hypothalamo-pituitary-testicular axis in normal men.
For elucidation of the effects of hyperprolactinemia on the hypothalamic-pituitary-testicular axis, five healthy men were exposed to sulpiride (300 mg/day by mouth); four among the five maintained hyperprolactinemia (71.6 to 95.3 ng/ml) for 78 days. Clomiphene citrate (CC), luteinizing hormone (LH)-releasing hormone, and human chorionic gonadotropin tests were performed before and after sulpiride treatment. The CC test, given as a measure of hypothalamic function, was carried out in each of the five volunteers before sulpiride treatment (control) and on days 14 (2 weeks) and 60 (2 months) of sulpiride administration. Each value of plasma LH stimulated by CC was integrated and expressed as a ratio of the integrated value obtained after administering CC at 2 weeks and 2 months to that from each control experiment. The mean ratio in the four subjects at 2 months (mean +/- standard deviation, 0.769 +/- 0.121) was significantly lower than that at 2 weeks (0.942 +/- 0.073; P less than 0.05) and before sulpiride treatment (1.000; P less than 0.01). Impairment of LH responses to CC by 2-month long sulpiride-induced hyperprolactinemia suggests that chronic hyperprolactinemia in men partly suppresses LH secretion by its inhibitory action on the hypothalamus.
D000328:Adult; D006063:Chorionic Gonadotropin; D002996:Clomiphene; D007987:Gonadotropin-Releasing Hormone; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000502:physiology*; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D008875:Middle Aged; D011388:Prolactin / Q000097:blood*; D013469:Sulpiride / Q000494:pharmacology*; D013737:Testis / Q000187:drug effects / Q000502:physiology*; D013739:Testosterone / Q000097:blood
D006063:Chorionic Gonadotropin; D002996:Clomiphene; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D013469:Sulpiride; D011388:Prolactin; D007986:Luteinizing Hormone