Effect of Luteinizing Hormone-Releasing Hormone on the Secretion of Luteinizing Hormone, Follicle-Stimulating Hormone, and Testosterone in Adult Male Rhesus Monkeys*

Abstract

Plasma levels of radioimmunoreactive LH [luteinizing hormone], FSH [follicle stimulating hormone] and testosterone (T) were assayed before and after administration of synthetic gonadotropin-releasing hormone (GnRH) to 5 chair-restrained rhesus monkeys with chronic indwelling venous catheters. I.v. injection of 1, 5 and 25 .mu.g or infusion of 1 .mu.g/min for 25 min of GnRH resulted in a significant increase in plasma levels of LH. However, no significant increases in plasma FSH levels were detected. Plasma levels of T were also elevated after administration of 25 .mu.g GnRH, but peak concentration of T lagged behind peak levels of LH by approximately 30 min. The male rhesus responds to GnRH administration by increased secretion of LH, followed by an increase in T levels. A concomitant increase in plasma FSH was not observed after treatment with GnRH in the doses used.