Intracellular pH and the stimulus-secretion coupling in insulin-producing RINm5F cells

L. Juntti-Berggren, P. Rorsman, W. Siffert, P. O. Berggren

Research output: Contribution to journalArticle

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Abstract

The regulation of intracellular pH (pH(i)) and its role in the insulin-secretory process were evaluated, by using the clonal insulin-secreting cell line RINm5F. Glyceraldehyde, lactate and dihydroxyacetone decreased pH(i), but only the first two released insulin. In the presence of extracellular Na+ the cells counteracted the acidification. Blocking the Na+/H+ exchange in acidic cells resulted in a drastic further lowering of pH(?), an effect not obtained under basal conditions. Whereas glyceraldehyde depolarized the cells, lactate was without effect. Dihydroxyacetone hyperpolarized the cells in the presence of extracellular Na+, but this effect disappeared when Na+ was excluded from the medium. Stimulation with glyceraldehyde resulted in increased free cytoplasmic Ca2+ concentration ([Ca2+](i)). Dihydroxyacetone and lactate had no effect on [Ca2+](i) in the presence of Na+, but lactate induced a decrease in [Ca2+](i) in Na+-deficient medium. In RINm5F cells the activity of the Na+/H+ antiport could not be augmented by activation of protein kinase C(PKC). Hence, in insulin-secreting cells a PKC-insensitive Na+/H+ antiport is the major mechanism restoring a decrease in pH(i). Acidification itself does not affect membrane potential, but may directly interact with the mechanisms regulating exocytosis.

Original languageEnglish
Pages (from-to)59-66
Number of pages8
JournalBiochemical Journal
Volume287
Issue number1
StatePublished - Jan 1 1992
Externally publishedYes

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Dihydroxyacetone
Glyceraldehyde
Lactic Acid
Insulin
Acidification
Protein Kinase C
Ion Transport
Insulin-Secreting Cells
pH effects
Secretory Pathway
Exocytosis
Membrane Potentials
Chemical activation
Cells
Membranes
Cell Line

ASJC Scopus subject areas

  • Biochemistry

Cite this

Juntti-Berggren, L., Rorsman, P., Siffert, W., & Berggren, P. O. (1992). Intracellular pH and the stimulus-secretion coupling in insulin-producing RINm5F cells. Biochemical Journal, 287(1), 59-66.

Intracellular pH and the stimulus-secretion coupling in insulin-producing RINm5F cells. / Juntti-Berggren, L.; Rorsman, P.; Siffert, W.; Berggren, P. O.

In: Biochemical Journal, Vol. 287, No. 1, 01.01.1992, p. 59-66.

Research output: Contribution to journalArticle

Juntti-Berggren, L, Rorsman, P, Siffert, W & Berggren, PO 1992, 'Intracellular pH and the stimulus-secretion coupling in insulin-producing RINm5F cells', Biochemical Journal, vol. 287, no. 1, pp. 59-66.
Juntti-Berggren L, Rorsman P, Siffert W, Berggren PO. Intracellular pH and the stimulus-secretion coupling in insulin-producing RINm5F cells. Biochemical Journal. 1992 Jan 1;287(1):59-66.
Juntti-Berggren, L. ; Rorsman, P. ; Siffert, W. ; Berggren, P. O. / Intracellular pH and the stimulus-secretion coupling in insulin-producing RINm5F cells. In: Biochemical Journal. 1992 ; Vol. 287, No. 1. pp. 59-66.
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