CAT and hypoxia: Normally, the mitochondrial and cytoplasmatic superoxide dismutase activity converts the radical superoxide to H2O2, and then it is reduced by catalase (Jackson et al., 2007); however, we demonstrated that in the oxidized POST-Hypoxia myoblasts, both the superoxide dismutase and catalase activities did not vary and as a consequence a O2•− and H2O2 could be accumulated within the cells that undergo oxidation.