Disruption of the plasma membrane leads to an influx of Na+ and Cl- but not an efflux of K+ in mouse hepatocytes and erythrocytes.

To determine what mechanisms might be involved in the maintenance of the known extra-/intracellular concentration gradients of Na+, Cl- and K+, small pieces of mouse liver and heparinized blood were appropriately cryofixed. The tissues were cryosectioned and cryosorbed at -100 degrees C or at -40 degrees C. The former temperature prevented diffusion of all ions as measured by electron probe x-ray microanalysis of the thin (0.1 micron) cryosorbed sections of the cells while the latter temperature allowed significant diffusion of Na+ and Cl- into the hepatocytes and erythrocytes but did not allow diffusion of K+ from the hepatocytes or the erythrocytes. These results indicate that the plasma membrane is involved in maintenance of the extra-/intracellular gradients of Na+ and Cl- but that intracellular association of K+ with macromolecules is the main mechanism responsible for maintenance of the extra-/intracellular K+ concentration gradient.