Salicylate inhibits the renal transport of inorganic sulfate in rat membrane vesicle preparations. Drug Metab. Dispos

SalIcyllc acid (SA) administration produces a pronounced enhance-ment of the renal clearance of inorganic sulfate in rats. The purpose of the present Investigation was to determine if SA inhibits the renal transport of Inorganic sulfate in rat kidney cortex brush border membrane (BBM) and basolateral membrane (BLM) vesicle prepa-rations. Sodium-dependent cotransport of inorganic sulfate was cx-amlned In BBM, and the values for KM and V, determined using nonlInear regression analysis, were 0.52 ± 0.41 mM and 2.84 ± 1.26 nmol/mg protein/lO 5cc, respectively (N = 7). Bicarbonate-depend-ent sulfate anion exchange was examined in BLM, and the values for KM and V, were 0.31 ± 0.14 mM and 0.83 ± 0.27 nmol/mg protein/lO 5cc, respectively (N = 5). SA inhibited sulfate transport Into both BBM and BLM preparations. The K, values, fitted using both competitive and noncompetitive inhibition models, were 19.4 ± 9.2 and 26.3 ± 12.2 mM (N = 3), respectively, for sodium/sulfate cotrans