Inositol Glycan Mimics the Action of Insulin on Glucose Utilization in Rat Adipocytes

Some of the actions of insulin may be mediated by the intracellular generation of an inositol phosphate glycan that modulates the activities of certain metabolic enzymes. The actions of this molecule were evaluated on glucose utilization in intact rat adipocytes. The inositol glycan led to the dose-dependent stimulation of glucose oxidation and lipogenesis. The extent of stimulation was similar to that observed for insulin. The stimulation of lipogenesis was seen only at high concentrations of glucose, suggesting regulation of processes distal to glucose uptake. The effects of the inositol glycan on intact adipocytes were specifically attenuated with inositol monophosphate in a dose dependent manner. These results further support a role for this substance as a second messenger for some of the actions of insulin, and indicate that the cellular uptake of the inositol glycan may occur by a specific transport system.