FACILITATION OF MATING-BEHAVIOR IN MALE HAMSTERS BY LHRH AND ACLHRH(5-10) - INTERACTION WITH THE VOMERONASAL SYSTEM

An intact vomeronasal organ is important for the reproductive physiology and behavior of many species. Vomeronasal sensory input is known to influence hormone levels especially LH, presumably by prior modulation of LHRH. LHRH has been shown independently to facilitate mating behavior in rodents of both sexes. In this study intracerebroventricular LHRH at a dose of 50 ng substantially relieved mating behavior deficits caused by prepubertal removal of vomeronasal organs from inexperienced male hamsters. Intranasal LHRH at a higher dose did not have this effect. Behavioral responses were recorded 30 mins after peptide or saline injection. The LHRH analog, AcLHRH(5-10) which we demonstrate does not induce LH release, did facilitate mating behavior in these tests, suggesting that LHRH peptides may facilitate male mating behavior via an extra-pituitary mode of action.