Transport of D-glucose by membrane vesicles from normal and avian sarcoma virus-transformed chicken embryo fibroblasts.
Transport of D-glucose was examined in membrane vesicles from normal and avian sarcoma virus (ASV)-transformed chicken embryo fibroblasts. The initial rates of D-glucose transport were found to be 3- to 5-fold higher for vesicles from glucose-starved normal cells and ASV-transformed cells when compared with transport rates for vesicles from normal cells and serum-starved normal cells. Cytochalasin B, phloretin, and diethylstilbestrol inhibited the initial rate of transport in all types of vesicles, and 2-deoxyglucose, 3-O-methylglucose, and galactose were competitive inhibitors. At D-glucose concentrations between 0.25 and 5 mM, vesicles from normal and ASV-transformed cells displayed saturation kinetics with a Km value of 5 mM for both types of vesicles, with transformed cell vesicles showing a 3-fold increase in Vmax compared with normal cell vesicles. At D-glucose concentrations between 5 and 25 mM the initial rate of D-glucose transport was proportional to D-glucose concentration. The vesicles also showed an inhibitor-sensitive efflux at rates similar to those observed for influx.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002462:Cell Membrane / Q000378:metabolism*; D002472:Cell Transformation, Viral; D002474:Cell-Free System; D002478:Cells, Cultured; D002642:Chick Embryo; D003470:Culture Media; D003571:Cytochalasin B / Q000494:pharmacology; D003847:Deoxyglucose / Q000378:metabolism; D004054:Diethylstilbestrol / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism*; D010693:Phloretin / Q000494:pharmacology; D013329:Structure-Activity Relationship
D003470:Culture Media; D003571:Cytochalasin B; D004054:Diethylstilbestrol; D003847:Deoxyglucose; D005947:Glucose; D010693:Phloretin