Bisexual behavior in male rats treated neonatally with antibodies to luteinizing hormone-releasing hormone

Investigated in 3 experiments, the possibility that luteinizing hormone-releasing hormone (LHRH) is involved in the process of sexual differentiation by injecting 163 male Wistar rat pups on Days 1 and 3 of life with specific antibodies to LHRH (AB-LHRH) or with normal rabbit serum. At maturity, Ss treated with AB-LHRH were as fertile as controls and their mount and intromission latencies and the postejaculatory interval were extended only slightly. However, they showed high levels of lordotic behavior, including ear wiggling, when castrated and primed with estrogen or with estrogen plus progesterone. Testosterone propionate, administered neonatally together with AB-LHRH, did not reverse these effects. Ss treated with AB-LHRH and castrated as adults did not respond to estrogen priming by releasing a surge of luteinizing hormone, a result indicating that they did not possess the female type of gonadotropin regulation. Findings indicate that neutralization of endogenous LHRH during neonatal life selectively blocked defeminization of behavior without affecting the process of masculinization. (39 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).