Abstract
Ouabain- and furosemide-insensitive and ATP-dependent Cl- uptake was demonstrated in rat renal membrane vesicles. Such a Cl- uptake activity was prominent in cortical plasma membrane fractions with high activities of Cl--ATPase and Na+, K+-ATPase. The membrane vesicles accumulated Cl- in an osmotically reactive manner with the following sequence of nucleotide specificity: ATP > ITP > UTP > GTP > CTP., β, γ-Methylene ATP, ADP and AMP had no effect. ATP-dependent Cl- uptake was markedly inhibited by a Cl--ATPase inhibitor, ethacrynic acid (0.3 mM), but not affected by an H+-ATPase inhibitor, N, N'-dicyclohexylcarbodiimide (0.1 mM). These findings suggest that an ethacrynic acid-sensitive and ATP-driven Cl- pump is present in the rat renal cortex.
