Lipoperoxide levels, glutathione status and glutathione peroxidase activity in liver and tumors of mice bearing the Lewis lung carcinoma.
Lipoperoxides, glutathione status and glutathione peroxidase activity have been determined in normal and neoplastic tissues of control and tumor-bearing mice, tissues from both groups being assayed 5, 7, 9, 11, 13 and 15 days after inoculation. The ratio of hepatic reduced: oxidized glutathione increased in tumor-bearing animals as the tumor increased in size. This ratio was 2.5-fold higher at 15 days than at 10 days after tumor inoculation. In both tumor and hepatic tissue the alteration in the ratio was the result of both an increase in reduced glutathione and a decrease in oxidized glutathione levels. In tumor tissue the progressively increasing reduced glutathione content correlated closely with tumor growth. The presence of a tumor did not significantly affect hepatic glutathione peroxidase activity and there was no significant difference between tumor enzyme activity assayed at 2-day intervals between 9 and 15 days after inoculation. The livers of tumor-bearing animals had significantly higher lipoperoxides than control mice, the levels increasing progressively with tumor growth. Tumor lipoperoxides were also high, usually in excess of the hepatic level. The lungs of nontumored littermates, which were compared with the carcinoma as reference tissue, showed no significant change in either glutathione peroxidase activity or lipoperoxide levels when monitored over the same period.更多