Meeting Abstract

P3.105  Saturday, Jan. 5  Evidence for a Gonadotropin-Inhibitory Hormone (GnIH) system within vertebrate gonads MCGUIRE, Nicolette L.*; UBUKA, Takayoshi; TSUTSUI, Kazuyoshi; BENTLEY, George E.; Univ of California, Berkeley; Univ of California, Berkeley; Waseda University; Univ 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 discovered in the hypothalamus of birds. Here we present different lines of evidence for the presence of a GnIH system in vertebrate gonadal tissues. We have previously demonstrated synthesis of GnIH and its receptor, RF-amide related peptide receptor (RFRPR), in galliform and passeriform birds. Thus the gonadal GnIH system may be a widespread property of vertebrate species. The functional significance of GnIH in the gonads is unclear, but the results suggest a role for GnIH in the local regulation of sex steroid synthesis or in the fine-tuning of sexual function at the level of the gonad.