The effect of dietary sodium restriction on leucocyte sodium transport in normotensive subjects and in patients with essential hypertension.

Dietary sodium restriction (10 mmol Na/day) for a period of 2 weeks did not result in any change in the blood pressure of 12 healthy young adults (mean age 21). There was also no change in their leucocyte sodium transport investigated immediately before the diet and on the last day. Sodium restriction (10 mmol Na/day) in 12 middle-aged hypertensive subjects (mean age 56) for the same period of time caused a significant fall in both systolic and diastolic blood pressure. The leucocyte total sodium efflux rate constant was initially low, but after the diet significantly increased towards the control value. The results are compatible with the theory that a circulating sodium transport inhibitor is present in patients with essential hypertension, and is related to salt intake.