Pflügers Archiv

, Volume 378, Issue 2, pp 93–97 | Cite as

Effects of Na+, K+ and Mg2+ on45Ca2+ uptake by pancreatic islets

  • Bo Hellman
  • Janove Sehlin
  • Inge-Bert Täljedal
Transport Processes, Metabolism and Endocrinology; Kidney, Gastrointestinal Tract, and Exocrine Glands

Abstract

Microdissected pancreatic islets of noninbredob/ob-mice were used to study ionic effects on the lanthanum-nondisplaceable45Ca2+ uptake by islet cells. Omission of Mg2+ from the incubation medium had no effect, but the45Ca2+ uptake was increased by omission of Na+ and decreased by omission of K+. Excess Mg2+ (1.2–15 mM) inhibited and excess K+ (4.7–25 mM) stimulated the45Ca2+ uptake in a concentration-dependent manner. Stimulation of45Ca2+ uptake in Na+-deficient islets was associated with an enhancement of the basal insulin release. Total abolishment of glucose-stimulated45Ca2+ uptake in K+-deficient islets did not preclude a significant secretory response to glucose. It is concluded that the lanthanum-nondisplaceable45Ca2+ uptake shows a partial correlation to insulin release.

Key words

Calcium uptake Insulin release Islets of Langerhans Lanthanum Magnesium Pancreatic islets Potassium Sodium 

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References

  1. 1.
    Gagerman, E., Idahl, L.-Å., Meissner, H. P., Täljedal, I.-B.: Insulin release. cGMP, cAMP and membrane potential in acetyl-choline-stimulated islets. Am. J. Physiol. (in press)Google Scholar
  2. 2.
    Hellman, B.: Calcium and pancreatic β-cell function. 3. Validity of the La3-wash technique for discriminating between superficial and intracellular45Ca. Biochim. Biophys. Acta540, 534–542 (1978)Google Scholar
  3. 3.
    Hellman, B., Idahl, L.-Å., Lernmark Å., Sehlin, J., Täljedal, I.-B.: The pancreatic β-cell recognition of insulin secretagogues. Effects of calcium and sodium on glucose metabolism and insulin release. Biochem. J.138, 33–45 (1974)Google Scholar
  4. 4.
    Hellman, B., Idahl, L.-Å., Lenzen, S., Sehlin, J., Täljedal, I.-B.: Further studies on the relationship between insulin release and lanthanum-nondisplaceable45Ca2+ uptake by pancreatic islets: effects of fructose and starvation. Endocrinology102, 1856–1863 (1978)Google Scholar
  5. 5.
    Hellman, B., Lenzen, S., Sehlin, J., Täljedal, I.-B.: Effects of various modifiers of insulin release on the lanthanumnondisplaceable45Ca2+ uptake by isolated pancreatic islets. Diabetologia13, 49–53 (1977)Google Scholar
  6. 6.
    Hellman, B., Sehlin, J., Täljedal, I.-B.: Effects of glucose on45Ca2+ uptake by pancreatic islets as studied with the lanthanum method. J. Physiol. (Lond.)254, 639–656 (1976)Google Scholar
  7. 7.
    Hellman, B., Sehlin, J., Täljedal, I.-B.: Calcium and secretion: distinction between two pools of glucose-sensitive calcium in pancreatic islets. Science194, 1421–1423 (1976)Google Scholar
  8. 8.
    Henquin, J.-C., Lambert, A. E.: Cationic environment and dynamics of insulin secretion. II. Effect of a high concentration of potassium. Diabetes23, 933–942 (1974)Google Scholar
  9. 9.
    Henquin, J.-C., Lambert, A. E.: Cationic environment and dynamics of insulin secretion. III. Effect of the absence of potassium. Diabetologia10, 789–794 (1974)Google Scholar
  10. 10.
    Henquin, J.-C., Lambert, A. E.: Cobalt inhibition of insulin secretion and calcium uptake by isolated rat islets. Am. J. Physiol.228, 1669–1677 (1975)Google Scholar
  11. 11.
    Lambert, A. E.: The regulation of insulin secretion. Rev. Physiol. Biochem. Pharmacol.75, 97–159 (1976)Google Scholar
  12. 12.
    Malaisse, W. J.: Role of cations. In: Insulin II. Handbook of exp. pharmacol 32/2 (Hasselblatt, A., v. Bruchhausen, F., eds.), pp. 145–155. Berlin-Heidelberg-New York: Springer 1975Google Scholar
  13. 13.
    Malaisse,-Lage, F., Malaisse, W. J.: Stimulus-secretion coupling of glucose-induced insulin release. III. Uptake of45calcium by isolated islets of Langerhans. Endocrinology88, 72–80 (1971)Google Scholar
  14. 14.
    Milner, R. D. G., Hales, C. N.: The role of calcium and magnesium in insulin secretion from rabbit pancreas studied in vitro. Diabetologia3, 47–49 (1967)Google Scholar
  15. 15.
    Milner, R. D. G., Hales, C. N.: Ionic mechanisms in the regulation of insulin secretion. In: The Structure and Metabolism of the Pancreatic Islets (Falkmer, S., Hellman, B., Täljedal, I.-B., eds.), pp. 489–493. Oxford: Pergamon Press 1970Google Scholar
  16. 16.
    Naber, S. P., McDaniel, M. L., Lacy, P. E.: The effect of glucose on the acute uptake and efflux of calcium-45 in isolated rat islets. Endocrinology101, 686–693 (1977)Google Scholar
  17. 17.
    Täljedal, I.-B.: Chlorotetracycline as a fluorescent Ca2+ probe in pancreatic islet cells. J. Cell Biol.76, 652–674 (1978)Google Scholar

Copyright information

© Springer-Verlag 1978

Authors and Affiliations

  • Bo Hellman
    • 1
  • Janove Sehlin
    • 1
  • Inge-Bert Täljedal
    • 1
  1. 1.Department of HistologyUniversity of UmeaUmeå 6Sweden

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