The actions of arginine and glucose on glucagon secretion are mediated by opposite effects on cytoplasmic Ca2+

Biochem Biophys Res Commun. 1987 Aug 31;147(1):309-14. doi: 10.1016/s0006-291x(87)80122-5.

Abstract

Cytoplasmic Ca2+ (Ca2+i) was monitored in single guinea-pig pancreatic alpha 2-cells exposed to modulators of glucagon release. The stimulatory amino acid arginine raised Ca2+i from 62 to 160 nM, whereas the inhibitor glucose reduced both the latter concentration and basal Ca2+i by 30%. Epinephrine which potentiates arginine-stimulated secretion by increasing cAMP, does so without affecting Ca2+i. The results indicate that glucagon secretion is positively modulated by Ca2+i. It is suggested that glucose-induced lowering of Ca2+i is a fundamental effect in cells where the sugar is readily metabolized.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arginine / pharmacology*
  • Calcium / physiology*
  • Cytoplasm / physiology
  • Epinephrine / pharmacology
  • Glucagon / metabolism*
  • Glucose / pharmacology*
  • Guinea Pigs
  • In Vitro Techniques
  • Islets of Langerhans / drug effects
  • Islets of Langerhans / physiology*

Substances

  • Glucagon
  • Arginine
  • Glucose
  • Calcium
  • Epinephrine