Accumulation of cadmium in pancreatic β cells is similar to that of calcium in being stimulated by both glucose and high potassium

Thomas Nilsson, Fredrik Rorsman, Per Olof Berggren, Bo Hellman

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

The transport of Cd2+ and the effects of this ion on secretory activity and metabolism were investigated in β cell-rich pancreatic islets isolated from obese-hyperglycemic mice. The endogenous cadmium content was 2.5 μmol/kg dry wt. After 60 min of incubation in a Ca2+-deficient medium containing 2.5 μM Cd2+ the islet cadmium content increased to 0.18 mmol/kg dry wt. This uptake was reduced by approx. 50% in the presence of 1.28 mM Ca2+. The incorporation of Cd2+ was stimulated either by raising the concentration of glucose to 20 mM or K+ to 30.9 mM. Whereas D-600 suppressed the stimulatory effect of glucose by 75%, it completely abolished that obtained with high K+. Only about 40% of the incorporated cadmium was mobilized during 60 min of incubation in a Cd2+-free medium containing 0.5 mM EGTA. It was possible to demonstrate a glucose-induced suppression of Cd2+ efflux into a Ca2+-deficient medium. Concentrations of Cd2+ up to 2.5 μM did not affect glucose oxidation, whereas, there was a progressive inhibition when the Cd2+ concentration was above 10 μM. Basal insulin release was stimulated by 5 μM Cd2+. At a concentration of 160 μM, Cd2+ did not affect basal insulin release but significantly inhibited the secretory response to glucose. It is concluded that the β cell uptake of Cd2+ is facilitated by the activation of voltage-dependent Ca2+ channels. Apparently, the accumulation of Cd2+ mimics that of Ca2+ also involving a component of intracellular sequestration promoted by glucose.

Original languageEnglish (US)
Pages (from-to)270-277
Number of pages8
JournalBBA - Molecular Cell Research
Volume888
Issue number3
DOIs
StatePublished - Oct 10 1986

Keywords

  • (Pancreatic β cell)
  • Cadmium accumulation
  • Insulin secretion
  • Stimulus-secretion coupling

ASJC Scopus subject areas

  • Biophysics
  • Cell Biology
  • Molecular Biology

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