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. 1992 Aug 1;285(Pt 3):973–978. doi: 10.1042/bj2850973

Ca2(+)-induced insulin secretion from electrically permeabilized islets. Loss of the Ca2(+)-induced secretory response is accompanied by loss of Ca2(+)-induced protein phosphorylation.

P M Jones 1, S J Persaud 1, S L Howell 1
PMCID: PMC1132890  PMID: 1323277

Abstract

Increasing the cytosolic Ca2+ concentration of electrically permeabilized rat islets of Langerhans caused rapid increases in insulin secretion and in 32P incorporation into islet proteins. However, the secretory responsiveness of permeabilized islets was relatively transient, with insulin secretion approaching basal levels within 20-30 min despite the continued presence of stimulatory concentrations of Ca2+. The loss of Ca2(+)-induced insulin secretion was accompanied by a marked reduction in Ca2(+)-dependent protein phosphorylation, but not in cyclic AMP-dependent protein phosphorylation. Similarly, permeabilized islets which were no longer responsive to Ca2+ were able to mount appropriate secretory responses to cyclic AMP and to a protein kinase C-activating phorbol ester. These results suggest that prolonged exposure to elevated cytosolic Ca2+ concentrations results in a specific desensitization of the secretory mechanism to Ca2+, perhaps as a result of a decrease in Ca2(+)-dependent kinase activity. Furthermore, these studies suggest that secretory responses of B-cells to cyclic AMP and activators of protein kinase C are not dependent upon the responsiveness of the cells to changes in cytosolic Ca2+.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Arkhammar P., Nilsson T., Berggren P. O. Glucose-induced changes in cytoplasmic free Ca2+ concentration and the significance for the regulation of insulin release. Measurements with fura-2 in suspensions and single aggregates of mouse pancreatic beta-cells. Cell Calcium. 1989 Jan;10(1):17–27. doi: 10.1016/0143-4160(89)90040-7. [DOI] [PubMed] [Google Scholar]
  2. Bjaaland T., Jones P. M., Howell S. L. Role of intracellular mediators in glucagon secretion: studies using intact and electrically permeabilized rat islets of Langerhans. J Mol Endocrinol. 1988 Nov;1(3):171–178. doi: 10.1677/jme.0.0010171. [DOI] [PubMed] [Google Scholar]
  3. Colca J. R., Brooks C. L., Landt M., McDaniel M. L. Correlation of Ca2+-and calmodulin-dependent protein kinase activity with secretion of insulin from islets of Langerhans. Biochem J. 1983 Jun 15;212(3):819–827. doi: 10.1042/bj2120819. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Colca J. R., Wolf B. A., Comens P. G., McDaniel M. L. Protein phosphorylation in permeabilized pancreatic islet cells. Biochem J. 1985 Jun 15;228(3):529–536. doi: 10.1042/bj2280529. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Grapengiesser E., Gylfe E., Hellman B. Dual effect of glucose on cytoplasmic Ca2+ in single pancreatic beta-cells. Biochem Biophys Res Commun. 1988 Jan 15;150(1):419–425. doi: 10.1016/0006-291x(88)90537-2. [DOI] [PubMed] [Google Scholar]
  6. Grapengiesser E., Gylfe E., Hellman B. Three types of cytoplasmic Ca2+ oscillations in stimulated pancreatic beta-cells. Arch Biochem Biophys. 1989 Jan;268(1):404–407. doi: 10.1016/0003-9861(89)90602-4. [DOI] [PubMed] [Google Scholar]
  7. Harrison D. E., Ashcroft S. J., Christie M. R., Lord J. M. Protein phosphorylation in the pancreatic B-cell. Experientia. 1984 Oct 15;40(10):1075–1084. doi: 10.1007/BF01971454. [DOI] [PubMed] [Google Scholar]
  8. Hedeskov C. J. Mechanism of glucose-induced insulin secretion. Physiol Rev. 1980 Apr;60(2):442–509. doi: 10.1152/physrev.1980.60.2.442. [DOI] [PubMed] [Google Scholar]
  9. Henquin J. C. The interplay between cyclic AMP and ions in the stimulus-secretion coupling in pancreatic B-cells. Arch Int Physiol Biochim. 1985 May;93(1):37–48. doi: 10.3109/13813458509104514. [DOI] [PubMed] [Google Scholar]
  10. Hii C. S., Jones P. M., Persaud S. J., Howell S. L. A re-assessment of the role of protein kinase C in glucose-stimulated insulin secretion. Biochem J. 1987 Sep 1;246(2):489–493. doi: 10.1042/bj2460489. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Hughes S. J., Chalk J. G., Ashcroft S. J. Effect of secretagogues on cytosolic free Ca2+ and insulin release at different extracellular Ca2+ concentrations in the hamster clonal beta-cell line HIT-T15. Mol Cell Endocrinol. 1989 Aug;65(1-2):35–41. doi: 10.1016/0303-7207(89)90162-7. [DOI] [PubMed] [Google Scholar]
  12. Hughes S. J., Christie M. R., Ashcroft S. J. Potentiators of insulin secretion modulate Ca2+ sensitivity in rat pancreatic islets. Mol Cell Endocrinol. 1987 Apr;50(3):231–236. doi: 10.1016/0303-7207(87)90021-9. [DOI] [PubMed] [Google Scholar]
  13. Jones P. M., Fyles J. M., Howell S. L. Regulation of insulin secretion by cAMP in rat islets of Langerhans permeabilised by high-voltage discharge. FEBS Lett. 1986 Sep 15;205(2):205–209. doi: 10.1016/0014-5793(86)80898-5. [DOI] [PubMed] [Google Scholar]
  14. Jones P. M., Persaud S. J., Howell S. L. Time-course of Ca2+-induced insulin secretion from perifused, electrically permeabilised islets of Langerhans: effects of cAMP and a phorbol ester. Biochem Biophys Res Commun. 1989 Aug 15;162(3):998–1003. doi: 10.1016/0006-291x(89)90772-9. [DOI] [PubMed] [Google Scholar]
  15. Jones P. M., Salmon D. M., Howell S. L. Protein phosphorylation in electrically permeabilized islets of Langerhans. Effects of Ca2+, cyclic AMP, a phorbol ester and noradrenaline. Biochem J. 1988 Sep 1;254(2):397–403. doi: 10.1042/bj2540397. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Jones P. M., Stutchfield J., Howell S. L. Effects of Ca2+ and a phorbol ester on insulin secretion from islets of Langerhans permeabilised by high-voltage discharge. FEBS Lett. 1985 Oct 21;191(1):102–106. doi: 10.1016/0014-5793(85)81002-4. [DOI] [PubMed] [Google Scholar]
  17. Knight D. E., Baker P. F. Calcium-dependence of catecholamine release from bovine adrenal medullary cells after exposure to intense electric fields. J Membr Biol. 1982;68(2):107–140. doi: 10.1007/BF01872259. [DOI] [PubMed] [Google Scholar]
  18. Knight D. E., von Grafenstein H., Athayde C. M. Calcium-dependent and calcium-independent exocytosis. Trends Neurosci. 1989 Nov;12(11):451–458. doi: 10.1016/0166-2236(89)90095-7. [DOI] [PubMed] [Google Scholar]
  19. Persaud S. J., Jones P. M., Howell S. L. Glucose-stimulated insulin secretion is not dependent on activation of protein kinase A. Biochem Biophys Res Commun. 1990 Dec 31;173(3):833–839. doi: 10.1016/s0006-291x(05)80862-9. [DOI] [PubMed] [Google Scholar]
  20. Pralong W. F., Bartley C., Wollheim C. B. Single islet beta-cell stimulation by nutrients: relationship between pyridine nucleotides, cytosolic Ca2+ and secretion. EMBO J. 1990 Jan;9(1):53–60. doi: 10.1002/j.1460-2075.1990.tb08079.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Prentki M., Matschinsky F. M. Ca2+, cAMP, and phospholipid-derived messengers in coupling mechanisms of insulin secretion. Physiol Rev. 1987 Oct;67(4):1185–1248. doi: 10.1152/physrev.1987.67.4.1185. [DOI] [PubMed] [Google Scholar]
  22. Suzuki K., Imajoh S., Emori Y., Kawasaki H., Minami Y., Ohno S. Calcium-activated neutral protease and its endogenous inhibitor. Activation at the cell membrane and biological function. FEBS Lett. 1987 Aug 17;220(2):271–277. doi: 10.1016/0014-5793(87)80828-1. [DOI] [PubMed] [Google Scholar]
  23. Tamagawa T., Niki H., Niki A. Insulin release independent of a rise in cytosolic free Ca2+ by forskolin and phorbol ester. FEBS Lett. 1985 Apr 22;183(2):430–432. doi: 10.1016/0014-5793(85)80825-5. [DOI] [PubMed] [Google Scholar]
  24. Vallar L., Biden T. J., Wollheim C. B. Guanine nucleotides induce Ca2+-independent insulin secretion from permeabilized RINm5F cells. J Biol Chem. 1987 Apr 15;262(11):5049–5056. [PubMed] [Google Scholar]
  25. Wang J. L., McDaniel M. L. Secretagogue-induced oscillations of cytoplasmic Ca2+ in single beta and alpha-cells obtained from pancreatic islets by fluorescence-activated cell sorting. Biochem Biophys Res Commun. 1990 Jan 30;166(2):813–818. doi: 10.1016/0006-291x(90)90882-n. [DOI] [PubMed] [Google Scholar]
  26. Wollheim C. B., Ullrich S., Meda P., Vallar L. Regulation of exocytosis in electrically permeabilized insulin-secreting cells. Evidence for Ca2+ dependent and independent secretion. Biosci Rep. 1987 May;7(5):443–454. doi: 10.1007/BF01362507. [DOI] [PubMed] [Google Scholar]
  27. Yaseen M. A., Pedley K. C., Howell S. L. Regulation of insulin secretion from islets of Langerhans rendered permeable by electric discharge. Biochem J. 1982 Jul 15;206(1):81–87. doi: 10.1042/bj2060081. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Zawalich W., Brown C., Rasmussen H. Insulin secretion: combined effects of phorbol ester and A23187. Biochem Biophys Res Commun. 1983 Dec 16;117(2):448–455. doi: 10.1016/0006-291x(83)91221-4. [DOI] [PubMed] [Google Scholar]
  29. van der Merwe P. A., Millar R. P., Davidson J. S. Calcium stimulates luteinizing-hormone (lutropin) exocytosis by a mechanism independent of protein kinase C. Biochem J. 1990 Jun 1;268(2):493–498. doi: 10.1042/bj2680493. [DOI] [PMC free article] [PubMed] [Google Scholar]

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