Stimulation of the insulin secretory mechanism following barium accumulation in pancreatic β-cells

Per Olof Berggren, Birgitta Andersson, Bo Hellman

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

Electrothermal atomic absorption spectroscopy was employed for measuring barium in β-cell-rich pancreatic islets microdissected from ob/ob-mice. Both the uptake and efflux of barium displayed two distinct phases. There was a 4-fold accumulation of barium into intracellular stores when its extracellular concentration was 0.26 mM. Unlike divalent cations with more extensive intracellular accumulation, the washout of Ba2+ was not inhibited by d-glucose. Ba2+ served as a substitute for Ca2+ both in maintaining the glucose metabolism after removal of extracellular Ca2+ and making it possible for glucose to stimulate insulin release. Furthermore, Ba2+ elicited insulin release in the absence of glucose and other secretagogues. The latter effect was reversible and was markedly potentiated under conditions known to increase the β-cell content of cyclic AMP. It is likely that the observed actions of Ba2+ are mediated by Ca2+, since Ca2+-dependent regulatory proteins, such as calmodulin, apparently cannot bind Ba2+ specifically.

Original languageEnglish (US)
Pages (from-to)320-328
Number of pages9
JournalBBA - Molecular Cell Research
Volume720
Issue number3
DOIs
StatePublished - Jun 8 1982

Keywords

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

ASJC Scopus subject areas

  • Biophysics
  • Cell Biology
  • Molecular Biology
  • Medicine(all)

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