The effect of cephaloridine on the stability of rat kidney lysosomes.

The administration of cephaloridine to rats caused a decrease in the excretion of acid phosphatase into the urine. The antibiotic itself had no effect on urinary acid phosphatase and inhibitors or proteolytic enzymes were not present in the urine from treated rats. Cephaloridine may therefore be stabilizing the lysosomal membrane in vivo and experiments with isolated lysosomes confirm this hypothesis. The lysosomal integrity was followed by measuring the acid phosphatase activity and the light scattering properties of the particles. A good correlation was obtained between these parameters in the case of thermal disruption and progesterone induced lysis of the lysosomes and low concentrations of cephaloridine (0.1-1.0 mmol/1) protected the lysosomes against this form of damage.