(Na+ + K+) ATPase inhibitors and intracellular electrolytes in essential hypertension.

White blood cell (WBC) Na+ and K+ concentrations, plasma (Na+ + K+)ATPase inhibition and blood pressure were determined in normotensive control subjects and patients with essential hypertension. While the untreated hypertensive group had significantly lower WBC K+ concentrations than the normotensive group (mean +/- SEM, 121.6 +/- 4.4 vs. 134.7 +/- 2.8 mEq/kg, p less than 0.05), no significant difference was observed in WBC Na+ concentrations between the 2 groups. The mean of plasma (Na+ + K+)-ATPase inhibition in untreated hypertensive patients was higher than that in normotensive controls (14.8 +/- 1.7 vs. 7.2 +/- 1.8%, p less than 0.05). The correlations between (Na+ + K+)ATPase inhibition and mean blood pressure and between WBC Na+/K+ ratio and mean blood pressure were significant (r = 0.278, p less than 0.05 and 0.270, p less than 0.05, respectively), but both were weak. However, untreated hypertensive patients with higher (Na+ + K+)ATPase inhibition had significantly higher WBC Na+/K+ ratios than untreated patients with less (Na+ + K+)ATPase inhibition. These results suggest a contribution of plasma (Na+ + K+)ATPase inhibition in the production of high blood pressure in a subset of patients with essential hypertension, which results in altered intracellular K+ concentrations.