Thyrotropin-releasing hormone provokes abnormal follicle-stimulating hormone (FSH) and luteinizing hormone responses in men who have pituitary adenomas and FSH hypersecretion.

Serum FSH ad LH concentrations after the administration of TRH were measured in 10 men who had pituitary adenomas associated with FSH hypersecretion. Similar measurements were made in 12 men who had pituitary adenomas but no FSH hypersecretion, in 10 age-matched, normal men, and in 5 men who had primary hypergonadism. The mean serum LH concentration in the men who had pituitary adenomas and FSH hypersecretion increased 136% after TRH administration, significantly greataer (P < 0.005) than the 48% increase in the normal men or the 51% increase in the men who had pituitary adenomas without FSH hypersecretion. Serum LH did not increase at all in the men who had primary hypoganadism. The serum FSH concentration did not increase in any of the normal men, in the men who had pituitary adenomas without FSH hypersecretion, or in the men who had primary hypogonadism, but did increase in 5 of the 10 men who had FSH hypersecretion; the mean increase in these 5 men was 38%. The exaggerated LH responses and the nonspecific FSH responses to TRH of the men who had pituitary adenomas associated with FSH hypersecretion suggest that control of both FSH and LH secretion by these adenomas is abnormal and, therefore, that these adenomas are likely gonadotroph cell adenomas.