Liver and Blood Cell Catalase Activity of Tumor-bearing Mice

Liver and blood cell catalase activity in mice with and without tumors of various sizes and origins was measured. Animals bearing tumors ⩾1.5 cm in size showed depression of leukocyte and/or liver catalase activity when compared with tumor-free animals, but this effect was not significant in mice with smaller tumors. No depression of erythrocyte catalase activity was observed.