Fig. 1.

(A) Total SOD, (B) Mn-SOD, (C) Cu/Zn-SOD, (D) GPx, and (E) CAT activities in the rats’ tongues of two age groups, namely 7 months (young group, n=8) and 22 months (old group, n=8). One unit of SOD is defined as the amount of enzyme needed to catalyze the dismutation of the superoxide (O₂⁻) radical by 50% at 25°C. One unit of GPx was defined as the amount of enzyme required to cause the oxidation of 1.0 nmol of NADPH to NADP⁺ per minute at 25°C. One unit of CAT was defined as the amount of enzyme required to produce 1.0 nmol of formaldehyde per minute at 25°C. Results are expressed as median values. SOD, superoxide dismutase; GPx, glutathione peroxidase; CAT, catalase; NADP, nicotinamide adenine dinucleotide phosphate. ^a)P<0.05. ^b)P<0.01 vs. the young group by the Mann-Whitney test.