title: Choline increases serum insulin in rat when injected intraperitoneally and augments basal and stimulated aceylcholine release from the rat minced pancreas in vitro.
abstract: Intraperitoneal injection of choline (30-90 mg.kg-1) produced a dose-dependent increase in serum insulin, glucose and choline levels in rats. The increase in serum insulin induced by choline (90 mg.kg-1) was blocked by pretreatment with the muscarinic acetylcholine receptor antagonists, atropine (2 mg.kg-1), pirenzepine (2 mg.kg-1) and 4-diphenylacetoxy-N-methylpiperidine (2 mg.kg-1) or the ganglionic nicotinic receptor antagonist, hexamethonium (15 mg.kg-1). The effect of choline on serum insulin and glucose was enhanced by oral glucose administration (3 g.kg-1). Choline administration was associated with a significant (P < 0.001) increase in the acetylcholine content of pancreatic tissue. Choline (10-130 microm) increased basal and stimulated acetylcholine release but failed to evoke insulin release from the minced pancreas at considerably higher concentrations (0.1-10 mm). Hemicholium-3, a choline uptake inhibitor, attenuated the increase in acetylcholine release induced by choline augmentation. Choline (1-32 mm) inhibited [3H]quinuclidinyl benzilate binding to the muscarinic receptors in the pancreatic homogenates. These data show that choline, a precursor of the neurotransmitter acetylcholine, increases serum insulin by indirectly stimulating peripheral acetylcholine receptors through the enhancement of acetylcholine synthesis and release.
authors.affiliation: Department of Biochemistry, Uludag University Medical School, 16059 Gorukle Kampusu, Bursa, Turkey. yesim@uludag.edu.tr
authors.forename: Yesim Ozarda
authors.initials: YO
authors.lastname: Ilcol
authors.forename: M Sibel
authors.initials: MS
authors.lastname: Gurun
authors.forename: Yavuz
authors.initials: Y
authors.lastname: Taga
authors.forename: Ismail H
authors.initials: IH
authors.lastname: Ulus
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002794:Choline / Q000008:administration & dosage* / Q000097:blood; D005947:Glucose / Q000008:administration & dosage / Q000494:pharmacology; D066298:In Vitro Techniques; D007274:Injections, Intraperitoneal; D007328:Insulin / Q000097:blood*; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology; D018733:Nicotinic Antagonists / Q000494:pharmacology; D010179:Pancreas / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D001786:Blood Glucose; D007328:Insulin; D018727:Muscarinic Antagonists; D018733:Nicotinic Antagonists; D005947:Glucose; D002794:Choline; D000109:Acetylcholine