Ca2+ binding and membrane fluidity in essential and renal hypertension.

1. Ca2+ -binding ability and membrane structure of red blood cells of patients with essential and renal hypertension were studied. 2. Ca2+ -binding ability of the erythrocyte membrane of patients with essential hypertension was found to be reduced by 30% compared with that of normotensive controls. 3. The rate of lateral diffusion of pyrene in the erythrocyte membrane of patients with essential hypertension was reduced both in the lipid bilayer and in the region of annular lipid compared with that of normotensive patients. 4. There are no differences either in Ca2+ -binding ability or in fluidity of the erythrocyte membrane of patients with chronic renal hypertension compared with that of normotensive individuals.