Effect of motilin on endogenous release of insulin in conscious dogs in the fed state.
The aim was to investigate the insulin-releasing activity of motilin during and after feeding. A single intravenous bolus injection of motilin (0.01-0.3 microg/kg) dose-dependently stimulated endogenous release of insulin in the postprandial state. The insulin-releasing activity of motilin in the fed state was completely abolished by pretreatment with atropine or hexamethonium and was partly inhibited by ondansetron. Truncal vagotomy also greatly suppressed the motilin-induced insulin release. While phentolamine significantly enhanced insulin release in response to motilin, propranolol significantly inhibited this response in both states. The motilin-induced insulin release in the fed states was not accompanied by any changes in glucose concentrations. In conclusion, while the physiological significance remains unclear, these results indicate that physiological doses of motilin stimulate endogenous release of insulin via a vagally cholinergic muscarinic pathway, and that adrenergic and 5-hydroxytryptamine3 receptors are also involved in this response, in the dog.
Suzuki
Hideki
H
Department of Surgery, Gunma University School of Medicine, 3-39-22 Showamachi, Maebashi 371-8511, Japan.
Kuwano
Hiroyuki
H
Mochiki
Erito
E
Haga
Norihiro
N
Shimura
Tatuo
T
Nomoto
Kenichi
K
Tanaka
Toshiyuki
T
Mizumoto
Akiyoshi
A
Itoh
Zen
Z
D000818:Animals; D001285:Atropine; D001786:Blood Glucose / Q000187:drug effects; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004386:Duodenum / Q000187:drug effects / Q000294:innervation; D005769:Gastrointestinal Motility / Q000187:drug effects; D018738:Hexamethonium; D007275:Injections, Intravenous; D007328:Insulin / Q000096:biosynthesis*; D009037:Motilin / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D017294:Ondansetron; D010646:Phentolamine; D019518:Postprandial Period; D011433:Propranolol; D013270:Stomach / Q000187:drug effects / Q000294:innervation; D014630:Vagus Nerve / Q000187:drug effects
D001786:Blood Glucose; D007328:Insulin; D018738:Hexamethonium; D017294:Ondansetron; D009037:Motilin; D001285:Atropine; D011433:Propranolol; D010646:Phentolamine