Table 2. Oxidative stress and GST, CAT and SOD enzyme activities in the rat liver.

Assays	Unit	Control	STZ	STZ/IN-1	STZ/IN-2
ROS	pmol/mg protein	3.1 ± 0.9	6.8 ± 1.7*	4.4 ± 1.2 (5.1 ± 1.3)	3.5 ± 1.0** (3.4 ± 1.2**)
GSH	nmol/mg protein	52.4 ± 18.5	33.5 ± 11.4	38.2 ± 15.0 (31.7 ± 16.3)	45.7 ± 16.3 (39.8 ± 13.9)
GST	nmol/min/mg protein	197.6 ± 47.6	98.9 ± 28.5*	138.3 ± 33.7 (152.4 ± 40.2)	168.5 ± 32.1** (173.5 ± 45.9)
CAT	μkat/mg protein	0.26 ± 0.05	0.11 ± 0.02*	0.16 ± 0.03 (0.13 ± 0.02)	0.20 ± 0.04** (0.17 ± 0.03**)
SOD	μkat/mg protein	2.52 ± 0.59	1.44 ± 0.34*	1.93 ± 0.43 (1.37 ± 0.37)	2.16 ± 0.61 (1.80 ± 0.51)

One μkat of CAT decomposes 1.0 μmole of H₂O₂ to oxygen and water per minute at a substrate concentration of 50 mM H₂O₂. One μkat of SOD inhibits the rate of reduction of cytochrome c by 50% in a coupled reaction, using xanthine and xanthine oxidase, at 25 °C

*P < 0.05 compared with that of control; **P < 0.05 compared with that of STZ

CAT = catalase; GSH = glutathione; GST = glutathione transferase; ROS = reactive oxygen species; SOD = superoxide dismutase; STZ = streptozotocin