Time-course of Ca2+-induced Insulin Secretion From Perifused, Electrically Permeabilised Islets of Langerhans: Effects of cAMP and a Phorbol Ester

Biochem Biophys Res Commun. 1989 Aug 15;162(3):998-1003. doi: 10.1016/0006-291x(89)90772-9.

Abstract

The pattern of insulin secretion from electrically permeabilised islets was studied in a perifusion system. Increases in intracellular Ca2+ stimulated insulin secretion in a dose-related manner, but the secretory response to Ca2+ was only transient, with permeabilised islets becoming rapidly insensitive to a stimulatory concentration of Ca2+. Cyclic AMP and the protein kinase C activator, phorbol 12-myristate 13-acetate (PMA), both stimulated Ca2+-induced insulin secretion from perifused permeabilised islets by increasing the maximum secretory response to Ca2+, and by maintaining elevated rates of secretion when the permeabilised islets had become insensitive to the stimulatory effects of Ca2+. These results suggest that cAMP and PMA may act partly by modifying the magnitude of the secretory response to Ca2+, and also by Ca2+-independent effects on the secretory mechanism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / pharmacology*
  • Cell Membrane Permeability
  • Cyclic AMP / pharmacology*
  • Electricity
  • In Vitro Techniques
  • Insulin / metabolism*
  • Insulin Secretion
  • Islets of Langerhans / metabolism*
  • Rats
  • Secretory Rate / drug effects
  • Tetradecanoylphorbol Acetate / pharmacology*
  • Time Factors

Substances

  • Insulin
  • Cyclic AMP
  • Tetradecanoylphorbol Acetate
  • Calcium