We studied the changes in the activities of superoxide dismutase(EC 1.15.1.1, SOD), catalase (EC 1.11.1.6), the production of superoxide radicals, and hydrogen peroxide in the rats´ liver that were treated with diethyldithiocarbamate (DDC), 1000 mg/kg body weight.
The results were summarized as follows:
1. At 1hr after the administration of´DDC, the rats´ liver showed considerably lower activities of Cu,Zn-SOD and Mn-SOD when compared with those of´the control rats (p<0.01, p<0.05). But the activities of´ the catalase were similar to the control values.
2. Activities of´Mn-SOD, Cu,Zn-SOD and catalase in the liver increased sequentially at 1hr, 3hr, 7hr, and- 15hr after the administration of DDC.
3. In the liver of´the rats treated with DDC, eventually at 15hr, the activities of Cu,Zn-SOD were similar to the control values, and the Mn-SOD increased by approximately 2 times. At 7hr, the activities of catalase were already 2 times higher than its control value..
4. Most of homogenates prepared from the liver of rats treated with DDC, the production of superoxide radicals slightly increased in comparison with those in the control groups, and the sequential changes in production tended to increase.
5. The production of hydrogen peroxide in the rats liver treated with DDC decreased in comparison
with its control value (p<0.05, p<0.01), and the production decreased sequentially.
In conclusion, it seems likely that the administration of DDC, a copper and metalloenzvne irreversible inhibitor sequentially decrease the production of hydrogen peroxide in rats liver following increase in the activUries of. SOD and catalase. Therefore, the SOD and catalase may be one of the factors in the liver defence mechanism for the oxygen toxicity.
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