Erythrocyte membrane lipids and cationic transport systems in men.

ABSTRACT

OBJECTIVE: The relationship between erythrocyte membrane and plasma lipids and various transmembrane erythrocyte cationic fluxes was examined in 53 normal men. DESIGN: Different measurements of erythrocyte transport systems were obtained Na(+)-Li+ countertransport activity; Na+, K+ cotransport activity; Na+, K(+)-ATPase pump activity and the ground membrane permeability for Na+ and K+ as well as the intra-erythrocyte Na+, K+ and Mg2+ concentrations. Plasma cholesterol, triglycerides, phospholipids, free fatty acids, low- and high-density lipoprotein cholesterol levels and the erythrocyte membrane contents of cholesterol, phospholipids and free fatty acids were obtained from fasting subjects. RESULTS: In single regression analysis the erythrocyte Na(+)-Li+ countertransport and Na+, K+ cotransport activities were negatively related to the erythrocyte membrane cholesterol, phospholipids and free fatty acids contents. The Na+, K(+)-ATPase pump activity as assessed by the ouabain-sensitive Na+ efflux was also inversely related to the membrane cholesterol and phospholipids contents. In multiple regression analysis the red blood cell Na(+)-Li+ countertransport activity was independently and negatively related to the membrane cholesterol and free fatty acids contents. CONCLUSION: Our data show that an elevated level of erythrocyte membrane lipids in normal men is accompanied by lower Na(+)-Li+ countertransport, Na+, K+ cotransport and Na+, K(+)-ATPase pump activities.