Role of chloride on carrier-mediated transport of p-aminohippurate in rat renal basolateral membrane vesicles

Effect of inorganic anions on p-amino3H]hippurate transport in renal basolateral membranes has been studied using the vesicles preloaded with unlabeled p-aminohippurate (countertransport condition). The uptake of p-amino3H]hippurate was stimulated by the outward gradient of unlabeled p-aminohippurate and the labeled substrate was accumulated into the vesicles against its concentration gradient in the presence of Cl-. The substitution of SCN- and SO4(2-) for Cl- in both sides of the vesicles depressed the initial rate and the overshoot magnitude of p-amino3H]hippurate uptake. These results suggest that Cl- may play an important role for the carrier-mediated transport system of organic anion in renal basolateral membranes.