title: Identification of ghrelin and its receptor in neurons of the rat arcuate nucleus.
abstract: Ghrelin, an acylated peptide originally identified in rat stomach as the endogenous ligand for the growth hormone secretagogue receptor (GHS-R), stimulates both food intake and growth hormone (GH) secretion. Ghrelin is predominantly synthesized by a subset of endocrine cells in the oxyntic gland of human and rat stomach. Previous studies using immunohistochemistry have shown that ghrelin is also present in the hypothalamic arcuate nucleus, a region critical for the control of feeding and GH secretion, but its expression pattern in this region and the details of its molecular form has yet to be clarified. In this report, we examined the presence of ghrelin in the arcuate nucleus using reverse-phase liquid chromatography combined with radioimmunoassay (RIA) and immunohistochemistry. Neurons in the arcuate nucleus were observed to react positively to ghrelin antibodies. In addition, we confirmed the existence of ghrelin mRNA expression using the reverse-transcription polymerase chain reaction (RT-PCR). We also observed the colocalization of GHS-R with neuropeptide Y (NPY) and growth-hormone-releasing hormone (GHRH) in the arcuate nucleus. The present study clearly indicates that ghrelin is synthesized in the arcuate nucleus, which will further our understanding of ghrelin's actions in the central nervous system, including feeding behavior and GH secretion.
authors.affiliation: Third Department of Internal Medicine, Miyazaki Medical College, University of Miyazaki, Kiyotake, Miyazaki 889-1692, Japan.
authors.forename: Muhtashan S
authors.initials: MS
authors.lastname: Mondal
authors.forename: Yukari
authors.initials: Y
authors.lastname: Date
authors.forename: Hideki
authors.initials: H
authors.lastname: Yamaguchi
authors.forename: Koji
authors.initials: K
authors.lastname: Toshinai
authors.forename: Tomoko
authors.initials: T
authors.lastname: Tsuruta
authors.forename: Kenji
authors.initials: K
authors.lastname: Kangawa
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Nakazato
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000166:cytology / Q000502:physiology*; D054439:Ghrelin; D013007:Growth Hormone-Releasing Hormone / Q000096:biosynthesis; D007150:Immunohistochemistry; D008297:Male; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D009478:Neuropeptide Y / Q000096:biosynthesis; D036361:Peptide Hormones / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000096:biosynthesis* / Q000235:genetics; D054440:Receptors, Ghrelin
chemical_list: D054439:Ghrelin; D009478:Neuropeptide Y; D036361:Peptide Hormones; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D054440:Receptors, Ghrelin; D013007:Growth Hormone-Releasing Hormone