[Changes in the structure of erythrocyte membrane and Na+. K+-ATPase activity in participants of the Soviet-Canadian trans-Arctic ski pass].

Changes in the structure of erythrocyte membranes and kinetics of the membrane-bound enzyme Na+, K(+)-ATPase were measured in members of the Canadian-Soviet transarctic ski pass that took place in March-May 1988. Hemoglobin content decreased at the Pole (by 22%) and partially recovered in Canada; phospholipids in erythrocyte membranes diminished at the Pole and in Canada (by 30%). During the pass water concentrations in membrane proteins and phospholipids increased significantly. Changes were found in rheological properties of membranes, e.g., viscosity of erythrocyte shadow suspensions at critical temperature (Tc) which is within the physiological range (36-38 degrees C) and viscosity in the temperature range 34-42 degrees C. Electric conductivity varied as a function of temperature (delta sigma(T)]. At 36-38 degrees C sigma showed abnormal variations. The integral intensity of IR-spectra of absorption bands of COp (peptide bonds) and P-O-C (phospholipids) decreased and the half-width of the COp absorption band increased during the pass. The activity of Na+, K(+)-ATPase of erythrocyte shadows diminished which was in correlation with membrane structure changes. The temperature optimum of Na(+)-, K(+)-ATPase occurred at 37-38 degrees C and coincided with the region of the structural phase transition detected by the authors.