GONADAL FUNCTION IN 50 MEN WITH UNTREATED PITUITARY ADENOMAS

Gonadal function was studied in 50 men with untreated pituitary adenomas. Seventy-four percent had impaired gonadotropin secretion, 82% had GH deficiency, 52% had TSH deficiency, 30% had ACTH deficiency, and 31% had PRL deficiency. Several unexpected abnormalities of gonadal function were found, including the following. 1) Four of the 14 men who could provide a semen specimen had normal total sperm counts in spite of subnormal serum testosterone concentration. 2) Although 35 of the 50 men (70%) had serum testosterone concentrations and LH responses to gonadotropin-releasing hormone that were either both normal or both subnormal, 11 men (22%) had subnormal serum testosterone concentrations but normal LH responses and 4 men (8%) had normal serum testosterone but subnormal LH responses. 3) Twelve men (24%) had supranormal serum FSH concentrations basally and/or in response to gonadotropin-releasing hormone. These 12 men had serum concentrations of testosterone that were low or low normal and serum concentrations of LH that were not elevated. hCG stimulation of 4 of the men who had low testosterone levels produced a 5-fold increase in mean serum testosterone concentration. Selective hypersecretion of FSH appears to occur commonly in men with pituitary adenomas and appears not to be due to primary hypogonadism. © 1979 by The Endocrine Society.