Effect of insulin on [3H]deoxy-D-glucose pharmacokinetics in the rat

Despite its increasing use in physiological animal investigations, there has been no systematic study of the whole body kinetics of 2-deoxy-D-glucose (2DG) or its modification by insulin. A previously proposed model that included processes representing transport across cell walls and intracellular phosphorylation of 2DG was investigated. The model predictions were compared with the plasma disappearance of 2DG observed in the rat following intravenous bolus injection. Experiments were performed during euglycemia at varying levels of hyperinsulinemia. The model was adequate to describe empirically the experimental data after a correction was made for urine loss. However, the variation in model parameters with plasma insulin concentration was not consistent with the expected action of insulin on cellular efflux. A possible explanation could be a shift in the rate-limiting step from glucose transport to another prephosphorylation process under conditions of high tissue uptake. This suggests that either intracellular or extracellular diffusion may constitute a significant barrier to 2DG (and glucose) uptake under some conditions.