On the stimulation of rat thymocyte 3-O-methyl-glucose transport by mitogenic stimuli.
Pretreatment of rat thymus lymphocytes with N-ethyl-maleimide prevents the stimulation of 3-O-methyl-glucose transport by concanavalin A or ionophore A23187 but does not affect the ability of concanavalin A to induce a rapid increase in cellular Ca2+take. N-ethyl-maleikide added after concanavalin A amplifies rather than prevents the subsequent stimulation of 3-O-methyl-glucose transport. Incubation of thymocytes with concanavalin A produces a decrease of 43% in the apparent Ki for phloretin, a competitive inhibitor of 3-O-methyl-glucose transport, without affecting the apparent Km for the substrate. Similarly, very low concentrations of cytochalasin B inhibit concanavalin A-stimulated glucose transport preferentially, without markedly affecting the unstimulated transport rates. The similarity between concanavalin A-stimulated 3-O-methyl-glucose transport in thymocytes and insulin-stimulated glucose transport in adipose tissue, with particular emphasis on the effects of the modifying agents described in this paper, is discussed.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D000001:Calcimycin / Q000494:pharmacology; D003208:Concanavalin A / Q000494:pharmacology; D003571:Cytochalasin B / Q000494:pharmacology*; D005033:Ethylmaleimide / Q000494:pharmacology*; D007700:Kinetics; D008757:Methylglucosides / Q000378:metabolism*; D008759:Methylglycosides / Q000378:metabolism*; D008934:Mitogens / Q000494:pharmacology*; D010693:Phloretin / Q000494:pharmacology*; D051381:Rats; D013601:T-Lymphocytes / Q000378:metabolism*
D008757:Methylglucosides; D008759:Methylglycosides; D008934:Mitogens; D003208:Concanavalin A; D000001:Calcimycin; D003571:Cytochalasin B; D005033:Ethylmaleimide; D010693:Phloretin