CAT and retinal degeneration: Further, to determine if oxidative stress is involved in two types of retinal degeneration rat models, the GSH level and activities of CAT and SOD in neural retinas were analyzed, including the retina sample obtained from RCS rat at 6 weeks (RCS) compared to an age-matched normal SD rat as the control (NC), and MNU-induced rat at 7 days (MNU) compared to a sample obtained from an age-matched no-treated rat as control (NC).