Influence of anoxia on glucose metabolism in pancreatic islets: lack of correlation between fructose-1,6-diphosphate and apparent glycolytic flux.
When equilibrated with O2-CO2 (95:5), pancreatic islets of non-inbred ob/ob-mice exhibited a sigmoidal dependence of 3H2O production on D-(5-3H)-glucose concentration; the rate was most sensitive to changes of glucose concentration around 5mM and tended to be maximum above about 15mM glucose. 3H2O production from more than 5 mM D-(5-3H)-glucose was about twice as fast as the production of 14CO2 from equimolar D-(U-14C)-glucose. Islets equilibrated with N2-CO2 (95:5) did not exhibit a sigmoidal dose-response curve for 3h2o production, the process being inhibited by anoxia at glucose concentrations above 5mM. Pieces of exocrine pancreas had a slower aerobic 3H2O production than the islets and showed a clear enhancement of the process during anoxia. In comparison with oxygenated islets, anoxic islets exhibited decreased concentrations of glucose-6-phosphate and increased concentrations of furctose-1,6-diphosphate. The concomitant inhibition of glycolytic flux may be due to a low lactate dehydrogenase activity in islets yielding a slow reoxidation of NADH and a slow phosphoglyceraldehyde oxidation under anaerobic conditions.
D000332:Aerobiosis; D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D005636:Fructosephosphates / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D005958:Glucosephosphates / Q000378:metabolism; D006019:Glycolysis; D000860:Hypoxia / Q000378:metabolism*; D007515:Islets of Langerhans / Q000378:metabolism*; D007773:Lactates / Q000378:metabolism; D008356:Mannoheptulose / Q000494:pharmacology; D051379:Mice; D008820:Mice, Obese; D014867:Water / Q000378:metabolism
D005636:Fructosephosphates; D005958:Glucosephosphates; D007773:Lactates; D014867:Water; D002245:Carbon Dioxide; D008356:Mannoheptulose; D005947:Glucose