Ratio of cytochromes in radiation-induced leukemia cells of mice

The content of cytochromes in various leukemia cells and normal thymocytes of mice was determined spectrophotometrically at room temperature and at the temperature of liquid nitrogen. The ratio of cytochrome c + c1 to cytochrome aa3 of primary thymic lymphomas, whether arising spontaneously in AKR mice or induced by x-irradiation in NIH Swiss mice, was similar to that of normal thymocytes. In contrast, three lines of transplantable ascites lymphoma cells, originally derived from radiation-induced lymphoma, showed a definitely higher ratio than that of normal thymocytes. The results revealed that the c + c1/aa3 ratio of the lymphoma cells increased in successive generations during serial passage of the cells in vivo