Metabolism of glucose and mannose anomers in pancreatic islets.
The alpha-anomers of D-glucose and D-mannose stimulate insulin release more efficiently than the corresponding beta-anomers. This coincides with higher glycolytic and oxidative fluxes in pancreatic islets exposed to alpha- than to beta-anomers. This situation may be attributable, in the case of alpha-D-glucose, not solely to the alpha-stereospecificity of phosphoglucose isomerase but also to that of phosphoglucomutase resulting in a higher islet content of glucose-1,6-bisphosphate, an activator of phosphofructokinase. Likewise, more aldohexose-bisphosphate accumulates in the islets exposed to alpha-D-mannose than in those incubated with beta-D-mannose. The anomeric specificity of hexose metabolism in pancreatic islets supports the fuel hypothesis for insulin release.
D000818:Animals; D005947:Glucose / Q000378:metabolism*; D006598:Hexosediphosphates / Q000378:metabolism; D006601:Hexoses / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D008358:Mannose / Q000378:metabolism*; D010732:Phosphofructokinase-1 / Q000378:metabolism; D010733:Phosphoglucomutase / Q000378:metabolism; D011972:Receptor, Insulin / Q000378:metabolism; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
D006598:Hexosediphosphates; D006601:Hexoses; D007328:Insulin; D010732:Phosphofructokinase-1; D011972:Receptor, Insulin; D010733:Phosphoglucomutase; D005947:Glucose; D008358:Mannose