Dissociation between changes in cytoplasmic free Ca2+ concentration and insulin secretion as evidenced from measurements in mouse single pancreatic islets

Sergei V. Zaitsev, Suad Efendić, Per Arkhammar, Alejandro M. Bertorello, Per Olof Berggren

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Simultaneous measurements of cytosolic free Ca2+ concentration and insulin release, in mouse single pancreatic islets, revealed a direct correlation only initially after stimulation with glucose or K+. Later, there is an apparent dissociation between these two parameters, with translocation of a and ε isoenzymes of protein kinase C to membranes and simultaneous desensitization of insulin release in response to glucose. Recovery of insulin release, without any concomitant changes in cytosolic free Ca2+ concentration, after addition of phorbol 12-myristate 13-acetate, okadaic acid, and forskolin supports the notion that the desensitization process is accounted for by dephosphorylation of key regulatory sites of the insulin exocytotic machinery.

Original languageEnglish (US)
Pages (from-to)9712-9716
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number21
StatePublished - Oct 10 1995



  • Islets of Langerhans
  • Kinetics
  • Protein phosphorylation

ASJC Scopus subject areas

  • General
  • Genetics

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