title: Expression of guanylin in "pars tuberalis-specific cells" and gonadotrophs of rat adenohypophysis.
abstract: The intestinal peptide guanylin regulates the electrolyte/water transport in the gastrointestinal epithelium by paracrine/luminocrine mechanisms. Because guanylin also circulates in the blood, we investigated the rat hypothalamo-pituitary region for expression and cellular localization of this peptide. Reverse transcriptase-PCR analyses with guanylin-specific primers revealed expression of the peptide in the pars tuberalis and pars distalis of the pituitary. Western blotting analyses in hypophyseal tissue extracts identified the expected 12.5-kDa immunoreactive peptide by using two different region-specific guanylin antisera. Light and electron microscopic immunocytochemistry with the same antisera localized guanylin in "pars tuberalis-specific cells" in the juxtaneural pars tuberalis adjacent to nerve endings and blood vessels of the hypothalamo-pituitary portal system and in gonadotrophic cells within the distal pars tuberalis and ventrolateral part of the pars distalis. The presence and cell-specific localization of guanylin within the hypothalamo-hypophyseal system indicate that this peptide may be specifically involved in paracrine and endocrine regulatory mechanisms.
authors.affiliation: Institute of Human Anatomy, University "La Sapienza," 00161 Rome, Italy.
authors.forename: L
authors.initials: L
authors.lastname: D'Este
authors.forename: H
authors.initials: H
authors.lastname: Kulaksiz
authors.forename: U
authors.initials: U
authors.lastname: Rausch
authors.forename: R
authors.initials: R
authors.lastname: Vaccaro
authors.forename: T
authors.initials: T
authors.lastname: Wenger
authors.forename: Y
authors.initials: Y
authors.lastname: Tokunaga
authors.forename: T G
authors.initials: TG
authors.lastname: Renda
authors.forename: Y
authors.initials: Y
authors.lastname: Cetin
mesh_terms: D000818:Animals; D005260:Female; D005768:Gastrointestinal Hormones; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology; D008297:Male; D016253:Microscopy, Immunoelectron; D045265:Natriuretic Peptides; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000378:metabolism* / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013347:Subcellular Fractions / Q000378:metabolism; D014882:Water-Electrolyte Balance / Q000502:physiology
chemical_list: D005768:Gastrointestinal Hormones; D045265:Natriuretic Peptides; D010455:Peptides; C072685:guanylin