Meeting Abstract

P2.164  Monday, Jan. 5  A novel neuropeptide system within the gonads: GnIH and GnIH-R in passerine songbirds MCGUIRE, N.L.*; UBUKA, T.; PERFITO, N.; BENTLEY, G.E.; University of California, Berkeley ; University of California, Berkeley ; University of California, Berkeley ; Helen Wills Neuroscience Institute and University of California, Berkeley nicolette@berkeley.edu

Many hormones that are classified as neuropeptides are synthesized in vertebrate gonads in addition to the brain. Receptors for these hormones are also expressed in gonadal tissue; thus there is potential for a highly localized autocrine or paracrine effect of these hormones on a variety of gonadal functions. In the present study we focused on gonadotropin-inhibitory hormone (GnIH), a neuropeptide that was first characterized as a hypothalamic regulator of pituitary function in birds. Here we present molecular, histological and physiological evidence for the presence and functional significance of a GnIH system in avian gonadal tissues. The presence of GnIH and its receptor, GnIH-R, in gonadal cells of passerine birds suggests a role for this system in the local regulation of sex steroid synthesis. Data from gonadal culture support this conclusion. Thus gonadal GnIH may fine-tune reproductive physiology and behavior via local regulation of steroid synthesis and its subsequent release into the periphery.