Effect of N-N'-diphenyl-p-phenylenediamine pretreatment on urinary enzyme excretion in cisplatin nephrotoxicity in rats.

Two days after cisplatin was injected into rats, urinary N-acetyl-beta-D-glucosaminidase (NAG) and gamma-glutamyltranspeptidase (gamma-GTP) activities increased. The urinary excretion of NAG continued to rise until 4 days after the injection of cisplatin, the last day examined. However, the increase in urinary gamma-GTP excretion which lasted for 2 days returned to its control level 4 days after cisplatin injection. The alkaline phosphatase activity in urine was unaffected by cisplatin injections. The antioxidant N-N'-diphenyl-p-phenylenediamine attenuated these increases in enzyme activities caused by cisplatin. The results of this study suggest that monitoring the change in urinary activities of some enzymes is the method of choice for detecting cisplatin nephrotoxicity and that the increase may involve the generation of free radicals by cisplatin.