CAT and Parkinson disease: The PD model, “1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)” showed increase in the levels of glutathione and catalase after 3 h exposure to 0.5 Gy gamma radiation (Yamaoka et al., 2002), which is further confirmed using mouse model of PD after whole body gamma radiation at 1.5 Gy (El-Ghazaly et al., 2015).