Alteration of hexose transport in avian erythrocytes by vinblastine and colchicine

Vinblastine and colchicine, compounds which effect the state of aggregation of microtubules, were investigated to determine if changes in the rate of sugar transport were produced by these compounds. Vinblastine accelerated 3-O-methylglucose entry into avian erythrocytes. At a concentration of 1.5 mm, transport was accelerated two-fold. The effect of vinblastine was not attributed to cell energy depletion or to increased entry by simple diffusion. Stimulation of transport did not require preincubation of the cells with vinblastine, and the effect was reversible. Colchicine (2 mm) inhibited 3-O-methylglucose entry in aerobic or anoxic intact red cells and in red cell ghosts. A change in the state of aggregation or activity of the microtubular system could represent a model for regulation of a membrane carrier. The present results would lend support to this model.