Evidence that polymyxin B is a glucose transport inhibitor.

The effect of polymyxin B on 3-O-methylglucose transport was studied in isolated rat adipocytes and erythrocytes. Polymyxin B (300 micrograms/mL) inhibited basal transport and insulin-stimulated transport of 3-O-methylglucose in adipocytes by 26.1 and 40.1%, respectively. Polymyxin B at concentrations of 300 and 3000 micrograms/mL inhibited transport of 3-O-methylglucose in erythrocytes by 20.0 and 40.8%, respectively. Polymyxin E at a concentration of 3000 micrograms/mL also inhibited, by 40.6%, the transport of 3-O-methylglucose in erythrocytes but 300 micrograms/mL of polymyxin E did not inhibit it significantly. These results indicate that polymyxin B inhibits glucose transport per se, as well as the insulin-dependent stimulation of glucose transport.