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.