title: 12-0-tetradecanoylphorbol-13-acetate and concanavalin A enhance glucose uptake in thymocytes by different mechanisms.
abstract: The effects of the tumor promoter 12-0-tetradecanoylphorbol-13-acetate (TPA) and the plant lectin concanavalin A (Con A) on glucose uptake in murine thymocytes were studied. TPA induces a rapid dose-dependent increase in the uptake of 2-deoxyglucose and in the transport of 3-0-methylglucose. Con A also elicits a time- and dose-dependent enhancement of 2-deoxyglucose uptake. The effect of Con A, however, is less pronounced. The effect of combined treatment of thymocytes with Con A and TPA is not additive. Cytochalasin B completely inhibits the basal, as well as TPA- and Con A-enhanced, 2-deoxyglucose uptake. Dexamethasone markedly inhibits basal 2-deoxyglucose uptake, but is less inhibitory to enhanced 2-deoxyglucose uptake induced by TPA and Con A. The effect of TPA on 2-deoxyglucose uptake and 3-0-methylglucose transport is refractory to inhibition by isobutyl methyl xanthine, dibutyryl cyclic AMP, and ethyleneglycol tetraacetic acid. These agents markedly inhibit the enhancement of 2-deoxyglucose (2-DOG) uptake by Con A. p-Bromophenacyl bromide, an inhibitor of phospholipase A2, also selectively inhibits Con A enhancement of 2-DOG uptake. Taken together, the results suggest that Con A and TPA exert their stimulatory effect on glucose uptake by different activating mechanisms, but they may share a final common transport pathway.
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D019325:3-O-Methylglucose; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D003994:Bucladesine / Q000494:pharmacology; D003208:Concanavalin A / Q000494:pharmacology*; D003837:Deoxy Sugars / Q000378:metabolism*; D003847:Deoxyglucose / Q000378:metabolism*; D004533:Egtazic Acid / Q000494:pharmacology; D005260:Female; D007700:Kinetics; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D008757:Methylglucosides / Q000378:metabolism*; D008759:Methylglycosides / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D010704:Phorbols / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013950:Thymus Gland
chemical_list: D003837:Deoxy Sugars; D008757:Methylglucosides; D008759:Methylglycosides; D010704:Phorbols; D003208:Concanavalin A; D019325:3-O-Methylglucose; D004533:Egtazic Acid; D003994:Bucladesine; D003847:Deoxyglucose; D013755:Tetradecanoylphorbol Acetate; D015056:1-Methyl-3-isobutylxanthine