Induction of Oviductal Carcinomas in B6C3F1 Mice Following Subchronic Co-Exposure to Ozone, 4-(N-Methyl-N-Nitrosamino)-1-(3-Pyridyl)-1-Butanone, and Dibutyl Phthalate

ABSTRACT The purpose of this study is the evaluation of the potential toxicity through subchronic exposure to 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and/or dibutyl phthalate (DBP) on ozone alone in B6C3F1 mice. Male and female B6C3F1 mice were exposed to 0.5 ppm ozone, 1.0 mg/kg NNK, 5,000 ppm DBP, and various combinations of these toxicants 6 h per day for 16- and 32-wk. Mortality was low during experiment and occurred from the 16- and 32-wk of test materials exposure. And decreases in mean body weights of both sexes of mice in all exposed groups were observed during the study. Absolute and relative lung, liver, kidney, adrenal gland, testis and ovary weights of all exposed groups of males and females were significant different from the weights of the respective control group. There were no test materials-related increased incidences of neoplasms in nearly all organs including target organ, lung. However, the incidence of oviductural carcinomas was observed in ozone, DBP, and ozone+NNK+DBP females in 32 wk study. Our data suggest that ozone does not induce lung cancer under our experimental condition, rather ozone, DBP, and ozone+NNK+DBP can induce oviductural carcinomas in B6C3F1 mice.