This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Triano, E. A. Articles by Triolo, A. J. Search for Related Content PubMed PubMed Citation Articles by Triano, E. A. Articles by Triolo, A. J.

Protective Effects of Trifluralin on Benzo(a)pyrene-induced Tumors in A/J Mice¹

Department of Pharmacology and Pathology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107

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.

¹ This investigation was supported by Grant R803486-03-0 from the Environmental Protection Agency and DORP (Dean's Overage Research Program) 080-01166 from Thomas Jefferson University.

² To whom requests for reprints should be addressed, at Department of Pharmacology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107.

Received 6/29/84. Accepted 11/ 5/84.