Although the toxic effects of cisplatinum on kidney have been appreciated for some time, the renal handling of cisplatinum and the mechanism by which the renal toxicity occurs are still incompletely understood. These mechanisms could be more easily defined if the molecular sites of interaction of cisplatin were recognized. This project is designed to define how the kidney handles cisplatin under normal conditions and after various pretreatments or other experimental conditions. Inherent in this study is an attempt to localize the sites of interaction of cisplatin and its intracellular binding sites. This section reports the sex and tissue specificity of platinum binding to DNA, the effect of cisplatinum on renal ATPase function in vivo and in vitro and the blockage of cisplatin-induced renal toxicity by sodium thiosulfate.