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Regulation of immunoreactive-insulin release from a rat cell line (RINm5F)

Praz, G. A.
Blondel, B.
Strauss, A. J.
Renold, A. E.
Published in Biochemical Journal. 1983, vol. 210, no. 2, p. 345-352
Abstract 1. An insulin-producing cell line, RINm5F, derived from a rat insulinoma was studied. 2. The cellular content of immunoreactive insulin was 0.19 pg/cell, which represents approx. 1% of the insulin content of native rat beta-cells, whereas that of immunoreactive glucagon and somatostatin was five to six orders of magnitude less than that of native alpha- or delta-cells respectively. 3. RINm5F cells released 7-12% of their cellular immunoreactive-insulin content at 2.8 mM-glucose during 60 min in Krebs-Ringer bicarbonate buffer. 4. Glucose utilization was increased by raising glucose from 2.8 to 16.7 mM. There was, however, no stimulation of immunoreactive-insulin release even when glucose was increased from 2.8 to 33.4 mM. A small stimulation of release was, however, found when glucose was raised from 0 to 2.8 mM. 5. Glyceraldehyde stimulated the release of immunoreactive insulin in a dose-dependent manner. 6. At 20 mM, leucine or arginine stimulated release at 2.8 mM-glucose. 7. Raising intracellular cyclic AMP by glucagon or 3-isobutyl-1-methylxanthine stimulated release at 2.8 mM-glucose with no additional stimulation at 16.7 mM-glucose. 8. Stimulation of immunoreactive-insulin release by K+ was dose-related between 2 and 30 mM. Another depolarizing agent, ouabain, also stimulated release. 9. Adrenaline (epinephrine) inhibited both basal (2.8 mM-glucose) release and that stimulated by 30 mM-K+. 10. Raising Ca2+ from 1 to 3 mM stimulated immunoreactive-insulin release, whereas a decrease from 1 to 0.3 or to 0.1 mM-Ca2+ lowered the release. 11. These findings could reflect a relatively specific impairment in glucose handling by RINm5F cells, contrasting with the preserved response to other modulators of insulin release.
Keywords Adenoma, Islet Cell/ secretionAmino Acids/pharmacologyAnimalsCations/pharmacologyCell LineEpinephrine/pharmacologyGlucagon/metabolismGlucose/pharmacologyGlyceraldehyde/pharmacologyInsulin/immunology/ secretionPancreatic Neoplasms/ secretionRatsSomatostatin/metabolism
PMID: 6134520
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PRAZ, G. A. et al. Regulation of immunoreactive-insulin release from a rat cell line (RINm5F). In: Biochemical Journal, 1983, vol. 210, n° 2, p. 345-352. https://archive-ouverte.unige.ch/unige:8970

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