Facilitatory role of neuropeptide Y on the onset of puberty: effect of immunoneutralization of neuropeptide Y on the release of luteinizing hormone and luteinizing-hormone-releasing hormone.

To examine the role of neuropeptide Y (NPY) in the first luteinizing hormone (LH) surge of puberty, the effect of passive immunoneutralization of NPY with antiserum against NPY (anti-NPY) injected centrally (third ventricle) or peripherally (jugular vein) was studied in pubertal female rats on the day of first proestrus. Both peripheral and central anti-NPY administration reduced the magnitude of the LH surge during the afternoon of first proestrus; however, the central route of administration appeared to be most effective. Centrally administered anti-NPY also reduced the magnitude of proestrous LH-releasing hormone (LHRH) release into pituitary portal blood in these rats. These results suggest that endogenous NPY plays a facilitatory role in the generation of the LHRH surge necessary for preovulatory gonadotropin release and puberty.