Whole body measurements of sodium turnover in offspring of patients with sustained essential hypertension.

The elimination rate (percent per day) of injected 22Na using a whole body measurement technique was significantly lower (5.8 +/- 1.5) in normotensive or borderline hypertensive offspring of essential hypertensive patients than in 15 age- and sex-matched, normotensive controls (7.3 +/- 1.0). There were no significant differences in exchangeable sodium, whole body potassium or in the urinary excretion of sodium, potassium and creatinine. The basis for the difference in turnover rate during week 1 is probably an alteration in the cellular handling of sodium (i.e. increased intracellular sodium) in the still normotensive offspring of patients with essential hypertension. The long-term (more than 100 days) whole body retention of 22Na was found to be only 0.1% of that injected, which justifies the use of this method on larger population groups.