Gonadal Function in Fifty Men with Untreated Pituitary Adenomas*

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Abstract
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. (J Clin Endocrinol Metab 48: 309, 1979)