Distribution of Glucose Carbons to Metabolic Products in the Perfused Rat Hindlimb Over a Range of Glucose Concentrations

Summary

To determine the distribution of glucose carbons to the major metabolic pathways as a function of glucose and insulin concentrations in fed rat muscle, rat hind-limbs were perfused with and without 100 nM insulin in the presence of 1-20 mM [U-¹⁴C]-D-glucose. The incorporation of radioactivity into CO₂, anionic metabolites released into the medium and muscle cell fractions were determined. The results indicate that the major metabolic fate of glucose taken up by muscle in the fed rat is conversion to anions released into the medium and that this process is saturable with increasing glucose concentrations. The data suggest that saturation of the glycolytic pathway is the major cause of the previously observed saturation of the glucose disposal rate associated with increasing glucose concentration.

Key-Words

Insulin - Muscle - Transport - Metabolism