Effects of N'methyl-N'-nitro-N-nitrosoguanidine and deoxycholic acid on the content of free radicals in rat serum

The aim of this study was to determine whether changes in serum free radicals may be useful for the early detection of precancerous conditions in the rat colon after treatment with a direct carcinogen (N-Methyl-N'-Nitro-N-Nitrosoguanidine, MNNG) and a secondary bile acid (deoxycholic acid, DCA) as a tumor promoter. It was shown that a significant increase in the concentrations of free radicals in sera of rats following their treatment with MNNG and DCA was observed as early as the 18th week after the beginning of the treatment. Since our results have shown that these alterations occured in parallel with neoplastic transformations in the rat colon, it suggests that the increase in serum free radicals reflected the precancerous situation in the animals and may be useful in the early detection of cancer development. The possible role of free radicals in deoxycholate-induced liver toxicity was discussed.