Effect of 2,4-Dinitrophenol on Osmoregulation in Isolated Kidney Slices

Abstract

Stern, Eggleston, Hems and Krebs¹ reported that slices of a number of guinea pig tissues swelled in isotonic solutions under anaerobic conditions. They suggested that the fluid balance of living tissues is not determined merely by physical forces, but by a mechanism dependent upon the supply of energy. Robinson² found that rat kidney slices swelled to a similar extent, mainly on account of an increase in the volume of intracellular water, when respiration was inhibited by small concentrations of cyanide. This swelling was reversed when the oxygen uptake recovered, as hydrogen cyanide distilled out of the medium. The water content of the slices varied inversely with their oxygen consumption over the whole range from normal respiration to complete inhibition. The amount of osmotic work required to maintain the water content of the slices as a steady state was calculated, and found to be proportional to their oxygen uptake. It was therefore suggested that the intracellular fluid was hypertonic, and that the normal volume and internal hypertonicity of the cells were maintained by active transport of water outwards across the cell membranes at the expense of energy directly derived from oxidation.