Stimulation of S-9 fraction metabolism in rat liver and breast by vital dyes.

The vital dyes neutral red (NR), methylene blue (MB) and trypan blue (TB) induced microsomal enzymes that metabolize the chemical carcinogens 2-aminoanthracene (2AA), 6-aminochrysene (6AC) and diaminofluorene (DAF). The Ames test was used as a method of assessing the amount of microsomal enzyme activity that occurred in rat breast and liver when treated with NR, MB, and TB. Livers were more readily induced than mammary glands of midpregnant rats. Liver S-9 fraction from rats treated with vital dyes showed an increase in revertant colonies for 2AA, DAF, and 6AC over that from untreated rats whereas breast S-9 fraction from rats treated with vital dyes showed an increase in revertant colonies for 2AA over untreated.