d-Glucose transport by membrane vesicles from quiescent, serum-stimulated, and SV40-transformed mouse 3T3 cells

Mixed membrane vesicle preparations from mouse embryo fibroblasts (Swiss 3T3) exhibited a facilitated diffusion transport system for d-glucose that showed many of the characteristics of the d-glucose transport system of whole cells: stereospecificity, counterflow, Michaelis-Menten kinetics with an apparent K_m similar to that of whole cells, and sensitivity to inhibition by cytochalasin B. Comparison of the stereospecific d-glucose transport activities of membrane vesicles from quiescent, serum-stimulated, and SV40 virus-transformed 3T3 cells showed no significant differences in rates of d-glucose uptake or efflux. This is in contrast to whole cells; quiescent 3T3 cells transported 6-deoxy-d-glucose at a significantly lower rate than serum-stimulated or SV40-transformed cells. These results indicate that d-glucose transport in quiescent vs. actively growing cells is regulated by cellular factors that are not retained in membrane vesicle preparations.