Leucine induces initial lowering of cytoplasmic Ca2+ in pancreatic beta-cells without concomitant inhibition of insulin release.
1989 (English)In: Biochemistry international, ISSN 0158-5231, Vol. 19, no 1, 83-7 p.Article in journal (Refereed) Published
The early effects of glucose and leucine on cytoplasmic Ca2+ and insulin release were compared in suspensions of cells prepared by dispersal of the beta-cell-rich pancreatic islets of ob/ob-mice. Adequate temporal resolution was achieved by continuously recording the 340/380 nm fluorescence excitation ratio from cells loaded with the Ca2+ indicator fura-2 and measuring insulin in the perifusate from cells mixed with polyacrylamide beads. Raising the glucose concentration from 3 to 20 mM resulted in concomitant reductions of cytoplasmic Ca2+ and insulin release during the first minute. Whereas 10 mM leucine was as efficient as glucose in inducing temporary lowering of cytoplasmic Ca2+, this amino acid did not depress insulin release. It is concluded that the initial decrease of cytoplasmic Ca2+ is a phenomenon coupled to stimulation of the metabolism. The leucine-induced lowering of Ca2+ may essentially reflect changes in cytoplasmic pools other than in a peripheral one regulating insulin release.
Place, publisher, year, edition, pages
1989. Vol. 19, no 1, 83-7 p.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-259873PubMedID: 2673247OAI: oai:DiVA.org:uu-259873DiVA: diva2:1061345