Effect of maleic acid on the kinetics of alpha-methyl-D-glucoside uptake by isolated rat renal tubules.

ALPHA-Methyl-D-glucoside has been used to study the invitro mechanism of the effect of maleic acid on sugar transport, using isolated rat renal tubule fragments. 6 mM maleate maximally inhibits the ability of the tubule to establish a concentration gradient for this model sugar with no evidence of ultrastructural changes. This inhibition is due to a 100% increase in efflux, as well as to a 50% decrease in influx with more prolonged incubation. The data presented here are consistent with those of other workers, but their work does not explain our results, which therefore deserve further investigation by other techniques.