Insulin binds to specific receptors and stimulates 2-deoxy-D-glucose uptake in cultured glial cells from rat brain

Abstract

The kinetics of 125I-insulin binding and physiological activity of insulin on glial cells cultured from brains of 1-day-old rats have been studied. Binding of 125I-insulin to cultured glial cells was specific, reversible, and time-dependent. Porcine and chicken insulin competed equally for 125I-insulin binding while other hormones or insulin analogs competed in proportion to their insulin-like biological activity. Incubation of glial cultures with insulin resulted in a time- and dose-dependent stimulation of 2-deoxy-D-glucose uptake. Maximal stimulation (190% of control) was observed with 18 nM insulin, and 0.1 nM insulin caused half-maximum effect. The stimulatory effect of insulin on 2-deoxy-D-glucose uptake was due to its effect on Vmax without affecting the Km. These observations suggest that insulin stimulates glucose uptake in glial cells cultured from rat brain, the effect mediated by insulin specific receptors.