Superoxide dismutase in various tissues from rabbits bearing the Vx-2 carcinoma in the maxillary sinus

Distribution profiles of superoxide dismutase isoenzymes in various tissues of rabbits with the Vx-2 carcinoma in the maxillary sinus were compared with those of control rabbits. Copper- and zinc-containing superoxide dismutase (Cu,Zn-SOD) activity in the liver of rabbits decreased significantly 3 weeks after transplantation. Manganese-containing superoxide dismutase (Mn-SOD) activity did not decrease significantly within 5 weeks after transplantation. In other tissues from the tumor-bearing rabbits, Cu,Zn-SOD and Mn-SOD activities were not changed within 5 weeks. No Mn-SOD activity and low Cu,Zn-SOD activity were detected in the Vx-2 carcinoma. These results suggest that the Vx-2 carcinoma has lost most of its ability to defend against oxygen toxicity and this ability decreased only in the liver of rabbits bearing the Vx-2 carcinoma in the maxillary sinus.