Intracellular electrolyte concentrations in epithelial tissue during various functional states.

The scanning electron microscope together with an energy dispersive system was used to quantify intracellular elemental concentrations of transporting epithelial cells under a variety of experimental conditions. In the frog skin, the Na transport pool is comprised of the intracellular compartments of all vital cells in the different cell layers, except the mitochondria rich cells. The Na content of this transport pool exchanges easily with the epithelial (outer) bathing solution. Vasopressin increases the Na permeability of the corial cell barrier. Proximal and distal tubular cells of the rat kidney show differences in the pattern of intracellular element concentrations. The distal tubular cell is more resistant to 20 min of ischemia than the proximal cell. The changes in intracellular electrolyte concentrations following 60 min of ischemia are reversible after reperfusing the kidney with blood for 60 min. In the cells of the frog skin and rat kidney, Na and K were equally distributed between the cytoplasm and the nucleus. Differences exist for P, Cl and dry weight.