The stimulus-secretion coupling of glucose-induced insulin release. XX. fasting: a model for altered glucose recognition by the B-cell.
The rate of glucose uptake and oxidation, the output of lactate, the net uptake of calcium, the release of preformed or newly synthesized insulin and, possibly to a lesser extent, the biosynthesis of proinsulin are all diminished in islets removed from fasted rats and exposed to glucose. Theophylline and dibutyryl-adenosine-3',5'-cyclic monophosphate fail to fully restore a normal secretory response to glucose, despite the fact that they increase lactate production by the islets from fasted animals. The insulinotropic action of other secretagogues, including glyceraldehyde, leucine, beta-hydroxybutyrate, and sulfonylurea is unaffected by prior fasting of the donor rats. The islets metabolism of glyceraldehyde is also unaffected by fasting. These data indicate that fasting is associated with a block in glucose metabolism in the early steps of glycolysis, prior to the triose-phosphate level, and suggest that the insulin secretory response to glucose may be closely dependent on the rate at which the hexose is metabolized by islet tissue.
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D005215:Fasting; D005260:Female; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D005985:Glyceraldehyde / Q000494:pharmacology; D006019:Glycolysis; D006601:Hexoses / Q000378:metabolism; D006885:Hydroxybutyrates / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism; D007930:Leucine / Q000494:pharmacology; D008954:Models, Biological; D010179:Pancreas / Q000378:metabolism*; D051381:Rats; D013453:Sulfonylurea Compounds / Q000494:pharmacology; D013806:Theophylline / Q000494:pharmacology
D006601:Hexoses; D006885:Hydroxybutyrates; D007328:Insulin; D013453:Sulfonylurea Compounds; D005985:Glyceraldehyde; D003994:Bucladesine; D013806:Theophylline; D007930:Leucine; D005947:Glucose