Summary
The uptake of45Ca2+ by a lanthanum-nondisplaceable pool in pancreatic islets was studied. Raising the extracellular D-glucose concentration from 3 to 20 mM stimulated the45Ca2+ uptake in hand-dissected islets of ob/ob-mice as well as in collagenase-isolated islets of ob/ob or normal mice. The effect was dose-dependent in the range of 0–20 mM D-glucose and was seen throughout a wide range of extracellular calcium concentrations (16 μmol — 2.56 mmol of Ca2+ added per litre of medium). The45Ca2+ uptake was also enhanced by other known insulin secretagogues (D-mannose, L-leucine, tolbutamide) and was uninfluenced by compounds lacking insulinreleasing capacity (3-O-methyl-D-glucose, L-glucose, D-galactose, D-leucine). The stimulatory effect of D-glucose was blocked by inhibitors of glucoseinduced insulin release (D-mannoheptulose, diazoxide, L-adrenaline). The results support the view that the lanthanum-nondisplaceable calcium pool is related to the insulin-releasing mechanism, although the exact nature of this relationship is still unclear.
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On leave from the Institute of Pharmacology and Toxicology, University of Göttingen, D-34 Göttingen, Germany Recipient of a research grant from the Deutsche Forschungsgemeinschaft (Le 348/1)
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Hellman, B., Lenzen, S., Sehlin, J. et al. Effects of various modifiers of insulin release on the lanthanum-nondisplaceable45ca2+ uptake by isolated pancreatic islets. Diabetologia 13, 49–53 (1977). https://doi.org/10.1007/BF00996327
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DOI: https://doi.org/10.1007/BF00996327