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Stimulation of insulin release by D-glucose in depolarized pancreatic islets

par Malaisse, Willy
Référence Cellular signalling, 9, 3-4, page (265-268)
Publication Publié, 1997-05

Article révisé par les pairs

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Résumé :

This study reevaluates the relevance of plasma membrane depolarization in the pancreatic islet B cell to the stimulation of insulin release by D glucose. In rat pancreatic islets exposed to increasing concentrations of D-glucose, a sigmoidal relationship is observed between the output of insulin and concentration of the hexose. The release of insulin recorded in the absence of D-glucose or at a non-stimulatory concentration (2.5 mM) of the hexose is significantly enhanced when the islets are incubated in the presence of the meglitinide analogue A-4166 (20 μM) or at a high concentration (30 mM) of extracellular K+. Nevertheless, even in the presence of A-4166 or at the high K+ concentration, increasing concentrations of D-glucose, up to 20 mM, still enhance, in a sigmoidal manner, the secretion of insulin, with a 15 fold or greater increment in insulin output relative to the value found in the absence of the hexose. These findings indicate that D-glucose provides a concentration-related signal for insulin release, that cannot be attributed solely to either the closing of ATP-sensitive K+ channels, the depolarization of the plasma membrane, or the role of D-glucose as a nutrient to cover the energy expenditure in the islet cells.