[Chronic sodium loading and circulating inhibitor of Na+,K+-ATPase in rats]

The effects of chronic sodium load on the activity of a circulating inhibitor of the Na+, K+-pump were measured in male Wistar rats. The inhibition by deproteinized plasma of renal Na+, K+-ATPase was higher in rats with high Na+ intake than in control animals (53.4 +/- 2.0 mumoles Pi.h-1 X mg-1 vs 66.6 +/- 2.6 mumoles Pi.h-1 X mg-1, p less than 0.01). The simultaneous rise in systolic blood pressure and the decrease in the hematocrit suggest that blood pressure, volemic expansion and the activity of this inhibitor may be somehow linked.