title: Gonadotropin-inhibitory hormone-stimulation of food intake is mediated by hypothalamic effects in chicks.
abstract: Gonadotropin-inhibitory hormone (GnIH), a 12 amino acid peptide, is expressed in the avian brain and inhibits luteinizing hormone secretion. Additionally, exogenous injection of GnIH causes increased food intake of chicks although the central mechanism mediating this response is poorly understood. Hence, the purpose of our study was to elucidate the central mechanism of the GnIH orexigenic response using 12 day post hatch layer-type chicks as models. Firstly, via mass spectrometry we deduced the chicken GnIH amino acid sequence: SIRPSAYLPLRFamide. Following this we used chicken GnIH to demonstrate that intracerebroventricular (ICV) injection of 2.6 and 7.8 nmol causes increased food intake up to 150 min following injection with no effect on water intake. The number of c-Fos immunoreactive cells was quantified in appetite-associated hypothalamic nuclei following ICV GnIH and only the lateral hypothalamic area (LHA) had an increase of c-Fos positive neurons. From whole hypothalamus samples following ICV GnIH injection abundance of several appetite-associated mRNA was quantified which demonstrated that mRNA for neuropeptide Y (NPY) was increased while mRNA for proopiomelanocortin (POMC) was decreased. This was not the case for mRNA abundance in isolated LHA where NPY and POMC were not affected but melanin-concentrating hormone (MCH) mRNA was increased. A comprehensive behavior analysis was conducted after ICV GnIH injection which demonstrated a variety of behaviors unrelated to appetite were affected. In sum, these results implicate activation of the LHA in the GnIH orexigenic response and NPY, POMC and MCH are likely also involved.
authors.affiliation: Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
authors.forename: Betty
authors.initials: B
authors.lastname: McConn
authors.affiliation: Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
authors.forename: Guoqing
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
authors.forename: Jiaqing
authors.initials: J
authors.lastname: Yi
authors.affiliation: Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Gilbert
authors.affiliation: Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Tokyo 162-8480, Japan; Suntory Foundation for Life Sciences, Bioorganic Research Institute, Osaka, 618-8503, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Osugi
authors.affiliation: Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Tokyo 162-8480, Japan.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Ubuka
authors.affiliation: Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Tokyo 162-8480, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Tsutsui
authors.affiliation: Division for Arts and Science, Faculty of Arts and Science, Kyushu University, Fukuoka 819-0395, Japan.
authors.forename: Vishwajit S
authors.initials: VS
authors.lastname: Chowdhury
authors.affiliation: Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Furuse
authors.affiliation: Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA. Electronic address: macline2@vt.edu.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Cline
mesh_terms: D000818:Animals; D030161:Avian Proteins / Q000737:chemistry / Q000494:pharmacology / Q000502:physiology*; D002645:Chickens; D004326:Drinking / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D007028:Hypothalamic Hormones / Q000737:chemistry / Q000494:pharmacology / Q000502:physiology*; D007031:Hypothalamus / Q000378:metabolism*; D007276:Injections, Intraventricular; D008297:Male; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D030161:Avian Proteins; D007028:Hypothalamic Hormones; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger
keywords: Chick; Gonadotropin-inhibitory hormone; Hypothalamus