Sodium flux and lipid spectrum in the erythrocyte membrane in essential hypertension.

In the erythrocyte membranes of normotensive individuals and patients with essential hypertension, sodium flux behavior, cholesterol content, phospholipid spectrum, and the fatty acid composition of the phospholipids were measured. There was no difference between normotensives and hypertensives in sodium influx in the erythrocyte. In both groups, 1 microM norepinephrine resulted in a significantly equal increase of sodium influx after an incubation period of 15 min. Compared with normotensives, erythrocytes in essential hypertensive patients showed a decreased sodium efflux. The cholesterol/phospholipid quotient of the erythrocyte membrane of hypertensive subjects increased in comparison with that of normotensive individuals. No differences between the two groups were found in the phospholipid pattern and in the fatty acid composition of phosphatidylserine/-inositol, -choline, and sphingomyelin. However, in phosphatidylethanolamine of the erythrocyte membrane in essential hypertensives in contrast to normals, a decreased content of the fatty acid fraction 22:0/20:3 and in increased content of the fatty acid fraction of 20:5/22:2/22:3 was found. The dependence of the Na turnover on the lipid spectrum of the erythrocyte membrane is discussed. The altered lipid composition of the erythrocyte membrane in essential hypertensives does not seem to cause the altered Na efflux behavior.