Choline increases serum insulin in rat when injected intraperitoneally and augments basal and stimulated aceylcholine release from the rat minced pancreas in vitro

Ilcol Y., Gurun M. S., Taga Y., Ulus I.

EUROPEAN JOURNAL OF BIOCHEMISTRY, vol.270, no.5, pp.991-999, 2003 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 270 Issue: 5
  • Publication Date: 2003
  • Doi Number: 10.1046/j.1432-1033.2003.03472.x
  • Journal Name: EUROPEAN JOURNAL OF BIOCHEMISTRY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.991-999
  • Keywords: precursor, acetylcholine, parasympathetic, muscarinic receptors, nicotinic receptor, MUSCARINIC RECEPTOR SUBTYPES, ISLET HORMONE-SECRETION, ACETYLCHOLINE-RELEASE, CONSCIOUS RATS, TYROSINE-HYDROXYLASE, GLUCAGON-SECRETION, BRAIN, CITICOLINE, STRIATUM, DISEASE
  • Bursa Uludag University Affiliated: Yes

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 mum) 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 [(3) H]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.