Stimulation of insulin release by alpha-D-glucose pentaacetate

Insulin release from rat pancreatic islets was stimulated by alpha-D-glucose pentaacetate (1.7 mM), but not by an equimolar concentration of beta-D-galactose pentaacetate. The secretory response to alpha-D-glucose pentaacetate was not reproduced by D-glucose and/or acetate, tested at concentrations equimolar to that of the hexose ester, and failed to be adversely affected by 3-O-methyl-D-glucose, even when used at a concentration sufficient to inhibit glucose-stimulated insulin release. These findings suggest that the insulinotropic action of alpha-D-glucose pentaacetate is attributable, in part at least, to the intracellular generation of D-glucose from the ester. The present work thus introduces selected esters of D-glucose as tools for the cellular supply of the hexose by a process that does apparently not involve its carrier-mediated transport across the plasma membrane. (C) 1997 Academic Press.