Relationship between Extracellular Na+ and the Total Ionized Ca2+ Content of Rat Pancreatic Islets

  • G. H. J. Wolters
  • M. Vonk
  • A. Pasma
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 211)


It is assumed that sodium ions, Na+, are involved in a Na-Ca exchange process at the β-cell membrane and in the mobilization of calcium ions, Ca2+, from intracellular stores4,5. Na-Ca exchange, which exchanges extracellular Na+ for intracellular Ca2+, has been observed in several cell types and has been characterized in detail in cardiac cells and membrane vesicles6. Na-Ca exchange depends on the electrochemical gradient of Na+ (and of Ca2+) across the cell membrane. This process is sensitive to changes in the membrane potential and the extracellular Na+ concentration, [Na+]o 6. If this process exists in β-cells, depolarization of the membrane will inhibit the exchange and enhance the intracellular Ca2+ concentration, [Ca2+]i, in the β-cells.


Choline Chloride Voltage Dependent Calcium Channel Induce Insulin Secretion Dependent Calcium Channel Total Calcium Content 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    B. Hellman, T. Andersson, P.-O. Breggren, and P. Rorsman, Calcium and pancreatic β-cell function. XI. Modification of 45Ca fluxes by Na+ removal, Biochem. Med. 24:143 (1980).PubMedCrossRefGoogle Scholar
  2. 2.
    B. Hellman and E. Gylfe, Glucose inhibits 45Ca efflux from pancreatic β-cells also in the absence of Na+-Ca2+ countertransport, Biochim. Biophys. Acta 770:136 (1984).PubMedCrossRefGoogle Scholar
  3. 3.
    B. Hellman, T. Honkanen, and E. Gylfe, Glucose inhibits insulin release induced by Na+ mobilization of intracellular calcium, FEBS Lett. 148:289 (1982).PubMedCrossRefGoogle Scholar
  4. 4.
    A. Herchuelz and W.J. Malaisse, Regulation of calcium fluxes in rat pancreatic islets: Dissimilar effects of glucose and of sodium ion accumulation, J. Physiol. 302:263 (1980).PubMedGoogle Scholar
  5. 5.
    A. Herchuelz, A. Sener and W.J. Malaisse, Regulation of calcium fluxes in rat pancreatic islets. Calcium extrusion by sodium-calcium countertransport, J. Membr. Biol. 57:1 (1980).PubMedCrossRefGoogle Scholar
  6. 6.
    J.P. Reeves and C.C. Hale, The stochiometry of the cardiac sodium-calcium exchange system, J. Biol. Chem. 259:7733 (1984).PubMedGoogle Scholar
  7. 7.
    G.H.J. Wolters, A. Pasma, J.B. Wiegman, and W. Konijnendijk, Glucose-induced changes in histochemically determined Ca2+ in β-cell granules, 45Ca uptake, and total calcium content of rat pancreatic islets, Diabetes 33:409 (1984).PubMedCrossRefGoogle Scholar
  8. 8.
    G.H.J. Wolters, A. Pasma, J.B. Wiegman, and W. Konijnendijk, Changes in histochemically detectable calcium and zinc during tolbutamide-induced degranulation and subsequent regranulation of rat pancreatic islets, Histochem. 78:325 (1983).CrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1986

Authors and Affiliations

  • G. H. J. Wolters
    • 1
  • M. Vonk
    • 1
  • A. Pasma
    • 1
  1. 1.Dept. of Experimental EndocrinologyUniversity of GroningenGroningenThe Netherlands

Personalised recommendations