Red Cell Sodium, Potassium and Calcium Content and Kinetics in Pregnancy-Induced Hypertension

Abstract

Intracellular concentrations of Na⁺,K⁺, and Ca²⁺ and efflux kinetics of Na⁺ and Ca²⁺ were measured in red cells from 15 patients with untreated PIH (PIH), 15 matched controls, and 23 non-pregnant subjects. Intracellular K⁺ was significantly lower in the patients with PIH compared to controls, but Na⁺ and total Ca²⁺ concentrations, total and ouabain-sensitive Na⁺, and Ca²⁺ efflux rate constants were similar. Efflux kinetics were unaltered when cells from hypertensive patients were incubated with control plasma and vice versa. Correlations were observed between intracellular Na⁺ and both maternal and gestational age, but not with parity. Mon-pregnant subjects were older than the pregnant patients, and apparent significant differences in red cell Na⁺ and Na⁺ efflux kinetics in pregnancy were not present when the data were corrected for age.

Our results suggest that intracellular K⁺ is relatively low in PIH, that cell Na⁺ and Ca²⁺ are unchanged, and that no stable Na⁺or Ca ²⁺transport inhibitor is present