EFFECT OF INSULIN ON GLUCOSE AND GLYCOGEN-METABOLISM AND LEUCINE INCORPORATION INTO PROTEIN IN CULTURED MOUSE ASTROCYTES

Insulin, following binding to its receptor, produces a dose- and time-dependent stimulation of entry of 2-deoxy-D-[U-C-14] glucose and glycogen synthesis from D-[U-C-14] glucose in cultured mouse astrocytes following differentiation. Maximal stimulation of both glucose entry (217% above basal) and of glycogen synthesis (209% above basal) was observed at an insulin concentration of 1.7 x 10(-7) M. Insulin also stimulates the incorporation of leucine into astrocytic proteins with maximal stimulation (156% above basal) at an insulin concentration of 1.7 x 10(-7) M, but no effect on leucine uptake was observed at an insulin concentration of 1.7 x 10(-6) M. These results, together with a previous demonstration that insulin and certain insulin analogues stimulate pyrimidine nucleoside incorporation into nucleic acid, indicate that insulin has diverse actions on biomacromolecular metabolism in cultured mouse astrocytes.