SOD1 and Alzheimer disease: Figure 4A showed that there was a corresponding increase in the CAT and SOD activities of rats treated with AD, which follows the pattern of Nrf2 induction in the same rats. The significant decrease of Nrf2 observed in untreated diabetic rats concurs with the reduced CAT activities in the same rats. Benipal and co-researchers [44] hypothesized that repetitive ROS production downregulates the expression of Nrf2.