Divalent cation transport in kidney slices. I. Properties of calcium transport in slices of rat kidney cortex and the effects of diuretics.

Correlative studies on transports of Ca2+ and Na+ and the properties of Ca2+ transport were carried out in rat kidney cortex slices. Ouabain had no effect on the Ca2+ transport but did inhibit the Na+ transport extensively. With addition of 2,4-dinitrophenol to the incubation medium, or under the anaerobic conditions, the effluxes of Ca2+ and Na+ were inhibited while the Ca2+ influx was enhanced significantly. Sulfhydryl inhibitors such as ethacrynic acid, mersalyl and p-chloromercuribenzoic acid suppressed Ca2+ efflux and stimulated Ca2+ influx. When the slices of kidney cortex were treated with these inhibitors, there was a reduction in the content of cellular ATP. The present results suggest that Ca2+ transport may be partly independent of Na+ transport, and that Ca2+ efflux may require energy-yielding processes.