Effect of sodium intake on intraerythrocyte sodium concentration in normotensive subjects and patients with untreated mild hypertension.

The effect of changing sodium intake for 2 weeks was studied. Twelve normotensive subjects and five patients with mild essential hypertension were given two different levels of sodium intake for 2 weeks. Overall there was no significant rise in blood pressure but all patients with hypertension had a rise in blood pressure as they went from a low to a high sodium intake. Plasma sodium was not altered but red cell sodium concentration was higher on the high sodium intake. This effect was observed in both normotensive and hypertensive people. Alterations observed in cell sodium concentration provide support for the hypothesis that increased dietary intake of sodium may induce hypertension by causing changes in cellular transport systems.