Protective effects of trifluralin on benzo(a)pyrene-induced tumors in A/J mice.
Trifluralin, a widely used herbicide, added to the diet before the p.o. administration of benzo(a)pyrene (BP) and fed continuously, significantly inhibited the induction of lung and forestomach tumors in female A/J mice. Dietary intake of trifluralin before the administration of BP resulted in a significant increase in glutathione in lung and forestomach but not in liver and glandular stomach. Trifluralin treatment also inhibited the binding of [3H]BP to liver and lung DNA, as well as to protein in the liver. Under these conditions, the protection against BP-induced lung tumors and perhaps forestomach tumors may be due to an elevation of tissue glutathione, resulting in a decreased binding of reactive metabolites of BP to macromolecules at these sites. The results indicate that trifluralin has a "blocking" effect in its inhibition of BP-induced tumors. Our studies show that trifluralin also inhibits chemical carcinogenesis in lung and forestomach when started in the diet 1 day after the administration of BP and fed continuously thereafter. In the case of lung, although maximum inhibition of tumors occurred when trifluralin was started 1 day after BP, there was significant protection at all time intervals (0 to 7 days) against lung tumors. The finding that trifluralin protects against BP tumorigenesis when started in the diet after the administration of the carcinogen clearly demonstrates that trifluralin also has a "suppressive" effect against BP-induced tumors.
D000818:Animals; D001564:Benzo(a)pyrene; D001579:Benzopyrene Hydroxylase / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D004247:DNA / Q000378:metabolism; D004032:Diet; D005260:Female; D005978:Glutathione / Q000378:metabolism; D008175:Lung Neoplasms / Q000139:chemically induced / Q000517:prevention & control*; D051379:Mice; D008805:Mice, Inbred A; D009929:Organ Size / Q000187:drug effects; D013274:Stomach Neoplasms / Q000139:chemically induced / Q000517:prevention & control*; D013997:Time Factors; D014052:Toluidines / Q000627:therapeutic use*; D014274:Trifluralin / Q000627:therapeutic use*
D014052:Toluidines; D001564:Benzo(a)pyrene; D004247:DNA; D014274:Trifluralin; D001579:Benzopyrene Hydroxylase; D005978:Glutathione