Glucose metabolism in mice

Abstract

Sixty normal mice were given single intravenous injections of glucose-U-C14. At varying times between 1 and 60 min following injection, either respiratory CO2 was collected or the animals were decapitated and blood, liver, and extrahepatic tissues were analyzed for glucose content and specific activity. In addition, C14 appearing in extrahepatic, nonglucose compounds soluble in 70% ethanol was determined. Data analysis indicated that all of the glucose in the postabsorptive mouse behaves as a single well-mixed pool which turns over with a half-time of approximately 5 min. Most glucose carbon utilized in the first 5 min was found in extrahepatic tissues. When half of the injected dose had been converted to nonglucose compounds, only 1.5% of the administered C14 was found in respiratory CO2. The respiratory C14O2 specific activity-time curve when compared to body glucose-C14 and extrahepatic tissue nonglucose-C14 at varying times indicated that glucose was oxidized to CO2 by way of a large intermediate pool of carbon and that a major part of the total CO2 produced by the postabsorptive mouse was derived from relatively nonlabeled sources of carbon.