Lymphocyte cell membrane handling of sodium and blood pressure control during salt restriction in normotensive subjects.

Intralymphocytic sodium and potassium concentrations, 22Na efflux rate constants (EFRC) and blood pressures (BPs) were studied in nine normotensive young males without a history of essential hypertension before, during and after 5 weeks of severe sodium depletion. Diastolic and median BPs decreased significantly as estimated by both ambulatory and home readings. A slight decrease in intralymphocytic potassium content and a significant increase in sodium content was found. Measurements of 22Na-EFRC were reduced by 15% in the ouabain-sensitive component of the sodium pump, while the absolute sodium efflux stayed constant during sodium depletion. These results are evidence of a primary inhibition of the sodium pump during salt restriction in normotensives.