The pituitary-testicular response to luteinising hormone releasing hormone administration to normal men

Abstract

The response of the pituitary and testis in normal men to the injection of LH-RH has been studied using single intravenous doses of either 25 mug or 100 mug. Serum LH levels rose with both doses but significant elevation of plasma testosterone was evident only following 100 mug of LH-RH. Though testosterone levels were elevated within 60 minutes, peak responses occurred from 4-12 hours post-injection. The rise in serum FSH levels was small or absent at 25 mug but was clearly present following 100 mug LH-RH, in general rising more slowly than LH levels but persisting for a longer period.

PIP: The pituitary and testicular response to luteinizing hormone-releasing hormone (LH-RH) was studied in 13 normal men. LH-RH w as injected in a single intravenous dose of 25 mcg or 100 mcg. Both doses produced increase in plasma testosterone levels, but only the 100 mcg dose caused significant increases at 90 minutes (p less than .005) and 210 minutes, post-injection (p less than .0025). Peak plasma testos terone concentrations occurred 4-12 hours after administration. 25 mcg LH-RH markedly raised luteinizing hormone (LH) levels in all subjects, though follicle stimulating hormone (FSH) release was not as distinctly increased. Both FSH and LH levels were markedly increased with the 100 mcg dose. The results indicate that a combined test of testicular and pituitary reserve is possible with 100 mcg LH-RH.