title: Vasodilatory effect of ghrelin, an endogenous peptide from the stomach.
abstract: Ghrelin is a novel growth hormone (GH)-releasing peptide, isolated from the stomach, which is identified as an endogenous ligand for GH secretagogues receptor. Although both ghrelin and its specific receptor are expressed in blood vessels, the cardiovascular effects of ghrelin remain unknown. To clarify whether ghrelin has a vasodilatory effect in humans, the response of forearm blood flow (FBF) to intra-arterial infusion of ghrelin was examined in eight healthy volunteers using a plethysmograph. In addition, hormonal responses to ghrelin were studied. Ghrelin increased FBF in a dose-dependent manner. Pretreatment with NG-monomethyl-l-arginine (l-NMMA), a nitric oxide synthase inhibitor, did not inhibit the FBF response to ghrelin, although l-NMMA significantly inhibited GH release. Serum insulin-like growth factor-I (IGF-I) level was not altered by ghrelin administration. Plasma cyclic guanosine 3', 5'-monophosphate level, a second messenger of nitric oxide, was also not altered. These results suggest that ghrelin has vasodilatory effects possibly through GH/IGF-I/nitric oxide-independent mechanisms.
authors.affiliation: Department of Cardiovascular Medicine, National Cardiovascular Center, Osaka, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Okumura
authors.forename: Noritoshi
authors.initials: N
authors.lastname: Nagaya
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Enomoto
authors.forename: Eiichiroh
authors.initials: E
authors.lastname: Nakagawa
authors.forename: Hideo
authors.initials: H
authors.lastname: Oya
authors.forename: Kenji
authors.initials: K
authors.lastname: Kangawa
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005542:Forearm / Q000098:blood supply / Q000502:physiology; D054439:Ghrelin; D006801:Humans; D007261:Infusions, Intra-Arterial; D008297:Male; D036361:Peptide Hormones; D010455:Peptides / Q000008:administration & dosage* / Q000502:physiology; D013270:Stomach / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology
chemical_list: D004791:Enzyme Inhibitors; D054439:Ghrelin; D036361:Peptide Hormones; D010455:Peptides