Erythrocytic ouabain-sensitive sodium efflux rate constant in pregnancy

To elucidate the physiology of active sodium transport (expressed as erythrocytic ouabian-sensitive sodium efflux rate constant = ERCos) in pregnancy and the influence of dietary sodium intake on that transport, active sodium transport was measured in 52 healthy pregnant women in week 16, 20, 24, 28, 32, 36 or week 38 of gestation. ERCos was not influenced by parity, dietary sodium intake or the development of pregnancy-induced hypertension. A statistical significant shift in ERCos was detected between week 24 and week 28 of gestation accompanied by a shift in intracellular sodium content. The meaning of this change in pregnancy remains unsolved, but an influence of ANP through A-II is suggested.