title: Existence of ghrelin-immunopositive and -expressing cells in the proventriculus of the hatching and adult chicken.
abstract: Ghrelin was isolated from the rat stomach as an endogenous ligand for the growth hormone secretagogue receptor (GHS-R) and has been found in the gastrointestinal tract of many vertebrates. Although the sequence and structure of chicken ghrelin has recently been determined, morphological characteristics of ghrelin cells in the chicken gastrointestinal tract are still obscure. In this study, we investigated ghrelin expression and distribution of ghrelin-producing cells in the hatching and adult chicken gastrointestinal tract by RT-PCR, immunohistochemistry and in situ hybridization. Ghrelin mRNA expression was observed mainly in the proventriculus in the hatching chicken and in the proventriculus, pylorus and duodenum of the adult chicken by RT-PCR. Ghrelin-immunopositive (ghrelin-ip) cells in the proventriculus were located at the mucosal layer but not in the myenteric plexus or smooth muscle layer. The number of ghrelin-ip cells in the adult chicken was greater than that in the hatching chicken. Interestingly, in the adult chicken, the number of ghrelin-ip cells were almost the same as that of ghrelin mRNA-expressing (ghrelin-ex) cells; however, in the hatching chicken, the number of ghrelin-ex cells was greater than that of ghrelin-ip cells. These results clearly demonstrate that ghrelin-producing cells exist in the chicken gastrointestinal tract, especially in the proventriculus, from hatching to adult stages of development, as well as in mammals.
authors.affiliation: Laboratory of Cell Biology, Department of Regulation Biology, Faculty of Science, Saitama University, 255 Shimo-ohkubo, Saitama, Saitama 338-8570, Japan.
authors.forename: Reiko
authors.initials: R
authors.lastname: Wada
authors.forename: Ichiro
authors.initials: I
authors.lastname: Sakata
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kaiya
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Nakamura
authors.forename: Yujiro
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Kenji
authors.initials: K
authors.lastname: Kangawa
authors.forename: Takafumi
authors.initials: T
authors.lastname: Sakai
mesh_terms: D000818:Animals; D002452:Cell Count; D002645:Chickens / Q000378:metabolism*; D004064:Digestive System / Q000378:metabolism; D054439:Ghrelin; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007413:Intestinal Mucosa / Q000378:metabolism; D036361:Peptide Hormones / Q000096:biosynthesis* / Q000276:immunology / Q000378:metabolism; D011531:Proventriculus / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013194:Staining and Labeling
chemical_list: D054439:Ghrelin; D036361:Peptide Hormones; D012333:RNA, Messenger