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Erik Renström

Erik Renström

Vice-chancellor

Erik Renström

A Subset of 50 Secretory Granules in Close Contact With L-Type Ca(2+) Channels Accounts for First-Phase Insulin Secretion in Mouse beta-Cells.

Author

  • Sebastian Barg
  • Lena Eliasson
  • Erik Renström
  • Patrik Rorsman

Summary, in English

Capacitance measurements were applied to mouse pancreatic beta-cells to elucidate the cellular mechanisms underlying biphasic insulin secretion. We report here that only <50 of the beta-cell's >10,000 granules are immediately available for release. The releasable granules tightly associate with the voltage-gated alpha(1C) Ca(2+) channels, and it is proposed that the release of these granules accounts for first-phase insulin secretion. Subsequent replenishment of the releasable pool by priming of previously nonreleasable granules is required for second-phase insulin secretion. The latter reaction depends on intragranular acidification due to the concerted action of granular bafilomycin-sensitive v-type H(+)-ATPase and 4,4-diisothiocyanostilbene-2,2-disulfonate--blockable ClC-3 Cl(-) channels. Lowering the cytoplasmic ATP/ADP ratio prevents granule acidification, granule priming, and refilling of the releasable pool. The latter finding provides an explanation to the transient nature of insulin secretion elicited by, for example, high extracellular K(+) in the absence of metabolizable fuels.

Department/s

  • Islet cell physiology
  • Diabetes - Islet Cell Exocytosis
  • Diabetes - Islet Patophysiology

Publishing year

2002

Language

English

Pages

74-82

Publication/Series

Diabetes

Volume

51 Suppl 1

Document type

Journal article

Publisher

American Diabetes Association Inc.

Topic

  • Endocrinology and Diabetes

Status

Published

Research group

  • Islet cell physiology
  • Diabetes - Islet Cell Exocytosis
  • Diabetes - Islet Patophysiology

ISBN/ISSN/Other

  • ISSN: 1939-327X