Effect of increasing concentrations of salt on the lysosomes of rat liver and Tetrrahymena pyriformis

Abstract

When cells are cooled below their freezing point there will be an increase in the concentration of solutes surrounding the subcellular organelles and, for that reason, we have studied the effect of different concentrations of a model solute, KCl, on the lysosomes of rat liver and Tetrahymena pyriformis. The latency of acid phosphatase and β-glucuronidase in homogenates of rat liver fell progressively after exposure to increasing concentrations of KCl and, although the sedimentable acid phosphatase also declined, the decrease was less marked. After exposure of homogenates of T. pyriformis to increasing concentrations of KCl, there was no decrease in the sedimentability of acid phosphatase although a progressive decline in the latency of the enzyme was demonstrated. The rat liver lysosomal membrane was shown to be only slighly permeable to KCl although the lysosomes of T. pyriformis were much more permeable to this salt. It seems possible that the disruptive effect of high concentrations of KCl is due to transiet osmotic pressure gradients which may arise when the concentration is reduced by dilution.