title: A novel avian hypothalamic peptide inhibiting gonadotropin release.
abstract: The neuropeptide control of gonadotropin secretion at the level of the anterior pituitary gland is primarily through the stimulatory action of the hypothalamic decapeptide, gonadotropin-releasing hormone (GnRH), which was originally isolated from mammals and subsequently from non-mammals. To date, however, an inhibitory peptide of gonadotropin release is unknown in vertebrates. Here we show, in a bird, that the hypothalamus also contains a novel peptide which inhibits gonadotropin release. Acetic acid extracts of quail brains were passed through C-18 reversed-phase cartridges, and then the retained material was subjected to the reversed-phase and cation-exchange high-performance liquid chromatography (HPLC). The peptide was isolated from avian brain and shown to have the sequence Ser-Ile-Lys-Pro-Ser-Ala-Tyr-Leu-Pro-Leu-Arg-Phe-NH(2). Cell bodies and terminals containing this peptide were localized immunohistochemically in the paraventricular nucleus and median eminence, respectively. This peptide inhibited, in a dose-related way, gonadotropin release from cultured quail anterior pituitaries. This is the first hypothalamic peptide inhibiting gonadotropin release reported in a vertebrate. We therefore term it gonadotropin-inhibitory hormone (GnIH).
authors.affiliation: Laboratory of Brain Science, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan. tsutsui@hiroshima-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Tsutsui
authors.forename: E
authors.initials: E
authors.lastname: Saigoh
authors.forename: K
authors.initials: K
authors.lastname: Ukena
authors.forename: H
authors.initials: H
authors.lastname: Teranishi
authors.forename: Y
authors.initials: Y
authors.lastname: Fujisawa
authors.forename: M
authors.initials: M
authors.lastname: Kikuchi
authors.forename: S
authors.initials: S
authors.lastname: Ishii
authors.forename: P J
authors.initials: PJ
authors.lastname: Sharp
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030161:Avian Proteins; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003370:Coturnix; D004797:Enzyme-Linked Immunosorbent Assay; D006062:Gonadotropins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007028:Hypothalamic Hormones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D008297:Male; D008969:Molecular Sequence Data; D010903:Pituitary Gland, Anterior / Q000187:drug effects* / Q000378:metabolism; D011863:Radioimmunoassay
chemical_list: D030161:Avian Proteins; D006062:Gonadotropins; D007028:Hypothalamic Hormones; C413752:gonadotropin-inhibitory hormone, Coturnix japonica