Rheologic properties of mammalian erythrocytes: relationship to transport ATPases.

Rheologic properties of erythrocytes and activities of their Ca(2+)-ATPase and Na+, K(+)-ATPase were analyzed together with standard erythrocyte values in seven mammalian species (man, rat, mouse, rabbit, hamster, guinea pig and dog). The number of erythrocytes in the blood of animals investigated correlated inversely with the mean cell volume (MCV) (r = -0.936, P = 0.002) and the mean cell hemoglobin content (MCH) (r = -0.923, P = 0.003). MCV and MCH also showed a high direct correlation with each other (r = 0.907, P = 0.005). The maximal erythrocyte deformability (DImax) measured with ektacytometry was inversely proportional to the MCV and MCH (r = -0.854, P = 0.014, and r = -0.940, P < 0.002, respectively). The MCV was also linearly related with the Na+, K(+)-ATPase activity (r = -0.791, P = 0.034). The major parameters of osmoscan (O' and Omax) and their derivatives (O'-Omin, Omax-Omin) were shown to be in a direct correlation with each other and with the activity of Na+, K(+)-ATPase in the whole erythrocytes except for the rabbit Na+, K(+)-ATPase. The activity of Ca(2+)-ATPase in the whole erythrocytes significantly correlated only with the O' and O'-Omin values. Thus, the activities of transport ATPases in mammalian red cells seem to be adjusted to the level required to maintain particular rheologic properties of the cells of one or other species.