Differential changes in superoxide dismutase activity in brain and liver of old rats and mice.
Superoxide dismutase (SOD) activity was measured in the brain and liver of 24-26- and 3-month-old rats. No significant age-related differences in Cu/Zn-SOD activity were found in any of the tissues studied. A small but significant increase in total SOD activity was observed in the whole brain (10-20%), cerebral cortex (11%), and hypothalamus (18%) of old rats, whereas a much more important increase in Mn-SOD activity was found in the whole brain (48%), cerebral cortex (70%), striatum (60%), and hypothalamus (30%). The increase of Mn-SOD activity in the brain of old rats suggests the enzyme may play an important role in the process of aging. Mn-SOD is found only in the mitochondrion, which could be an important site of oxygen free radical production, and a significant increase in the enzyme activity was also found in the lung of hypoxic rats. A significant decrease in total SOD and Mn-SOD activity was observed in the liver of old rats. Preliminary experiments in 23-24-month-old mice similarly showed an increase and a decrease in total SOD and Mn-SOD activity, respectively, in the whole brain and liver. These results suggest that the regulatory mechanisms of Mn-SOD in the brain and liver vary differentially with age.
D000375:Aging; D000818:Animals; D001921:Brain / Q000201:enzymology / Q000254:growth & development*; D008099:Liver / Q000201:enzymology / Q000254:growth & development*; D008297:Male; D051379:Mice; D009928:Organ Specificity; D051381:Rats; D011919:Rats, Inbred Strains; D013482:Superoxide Dismutase / Q000378:metabolism*
D013482:Superoxide Dismutase