Chronic Exposure to High Glucose and Impairment of K+-Channel Function in Perifused Rat Pancreatic Islets

  1. Riccardo Vigneri
  1. Department of Endocrinology, University of Catania Catania, Italy
  1. Address correspondence and reprint requests to Dr. Francesco Purrello, Cattedra di Endocrinologia, Ospedale Garibaldi, Piazza Santa Maria di Gesù, 95123 Catania, Italy.

Abstract

Prolonged exposure to high glucose levels impairs the ability of pancreatic islets to secrete insulin as a response to that stimulus. Because glucose, like other insulin secretagogues, elicits insulin secretion by inhibiting the ATP-sensitive K+ channels, in this study, we investigated the effect of prolonged (24-h) exposure of rat pancreatic islets to high (16.7 mM) glucose concentration on 86Rb efflux (used as a tracer for K+). The data obtained indicate that islets exposed to high glucose concentration have impaired function of the glucose-sensitive K+ channel, this phenomenon is temporarily related to a defective response of glucose-induced insulin release, and these alterations are reversible.

  • Received November 16, 1989.
  • Revision received December 12, 1989.
  • Accepted December 12, 1989.
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