EFFECTS OF VANADATE ON ORGANIC ION ACCUMULATION IN RAT RENAL CORTICAL SLICES

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  • 1 January 1982
    • journal article
    • research article
    • Vol. 220  (3) , 540-546
Abstract
NaVO3 is a potent inhibitor of Na-K-ATPase. p-Aminohippurate (PAH) and tetraethylammonium accumulation in rat renal cortical slices was inhibited by in a dose-dependent manner at medium VO3- concentrations from 10-6-10-3 M. Inhibition was reversible at VO3- concentrations < 1.5 .times. 10-5 M. The slice content of V (7.5-325 .mu.M V/g wt tissue) was linearly related to medium VO3- concentrations ranging from 10-5-10-3 M. The ability of slices to generate glucose and ammonia was not impaired by medium VO3- concentrations up to 5 .times. 10-4 M, a concentration that maximally inhibited organic ion accumulation. Increasing medium K+ concentrations potentiated VO3- inhibition of PAH accumulation which correlated with inhibition of Na pump activity, as determined by 42K+ uptake. I.p. VO3- administration (1 or 5 mg V/kg) to rats produced a profound diuresis and natriuresis during the 1st h. Inhibition of PAH accumulation of renal slices from these rats was related to tisue V concentrations. Evidently, VO3- exerts its action on proximal tubule transport of PAH by inhibition of Na-K-ATPase.