title: Role of ghrelin in the regulation of vasopressin release in conscious rats.
abstract: GH secretagogue (GHS) is a small, synthetic compound that has the potential to stimulate GH release via its specific receptors (GHS-R). Ghrelin is a novel 28-amino acid peptide recently isolated from human and rat stomach, and it is thought to be the endogenous ligand for GHS-R. Ghrelin has a variety of physiological functions such as the stimulation of GH release or the increase of food intake by activating NPY neurons. In the present study, we investigated the effects of ghrelin on AVP release in conscious rats. Intracerebroventricular (icv) administration of ghrelin increased the plasma AVP concentration in a dose-dependent manner (1-1000 pmol/rat), and its effect was observed as late as 60 min after the administration. Icv injection of ghrelin caused no significant change in plasma osmolality, plasma volume, or arterial blood pressure. Iv administration of ghrelin (10 nmol/rat) also increased the plasma AVP concentration, which was accompanied by a significant decrease in arterial blood pressure. Pretreatment with antiserum against NPY significantly reduced the plasma AVP increase induced by icv administration of ghrelin. These results suggest that ghrelin plays a stimulatory role in AVP release, which is possibly mediated by NPY neurons.
authors.affiliation: First Department of Internal Medicine, Nagoya University School of Medicine, Nagoya 466-8550, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Ishizaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Murase
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Sugimura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kakiya
authors.forename: Hisashi
authors.initials: H
authors.lastname: Yokoi
authors.forename: Kazushige
authors.initials: K
authors.lastname: Tachikawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Arima
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Miura
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Oiso
mesh_terms: D000818:Animals; D019138:Antibodies, Blocking / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D001798:Blood Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D054439:Ghrelin; D007275:Injections, Intravenous; D007276:Injections, Intraventricular; D007700:Kinetics; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D009478:Neuropeptide Y / Q000037:antagonists & inhibitors / Q000502:physiology; D036361:Peptide Hormones; D010455:Peptides / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000097:blood; D014667:Vasopressins / Q000097:blood / Q000378:metabolism*
chemical_list: D019138:Antibodies, Blocking; D001798:Blood Proteins; D054439:Ghrelin; D009478:Neuropeptide Y; D036361:Peptide Hormones; D010455:Peptides; D014667:Vasopressins; D012964:Sodium