title: Sodium pump parameters of red blood cells in men, women and women taking oral contraceptives.
abstract: Three parameters of the sodium pump, the sodium efflux rate, the intracellular sodium content (Nai) and the number of sodium, potassium ATPase sites per red blood cell (sites/rbc) were measured simultaneously on erythrocytes from normal men and women and from women taking oral contraceptives. Significant (p less than 0.002) differences were obtained between normal men and women for sodium efflux (1.68 +/- 0.15 vs 1.52 +/- 0.12 mmoles/L rbc/hr). Among the three measured parameters, there was an inverse relationship (r = -0.74) between Nai and sites/rbc and a linear correlation (r = 0.89) between efflux per site and Nai. A positive correlation (r = 0.78) between the sites/rbc and a first-order rate constant for Na efflux/rbc suggests that one component of the rate constant is the number of sites/rbc. Values for a second-order rate constant, calculated from the assumption that efflux/rbc depends on both Nai and the number of sites/rbc, were similar for normal men and women but significantly (p less than 0.001) higher for women taking oral contraceptives.
mesh_terms: D000328:Adult; D001665:Binding Sites / Q000187:drug effects; D001692:Biological Transport / Q000187:drug effects; D003276:Contraceptives, Oral / Q000009:adverse effects*; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000139:chemically induced; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010042:Ouabain / Q000097:blood; D012727:Sex Characteristics; D012964:Sodium / Q000097:blood*
chemical_list: D003276:Contraceptives, Oral; D007473:Ion Channels; D010042:Ouabain; D012964:Sodium