INDUCTION OF LUNG AND LIVER-TUMORS BY FLUORANTHENE IN A PREWEANLING CD-1 MOUSE BIOASSAY

Fluoranthene (FA), a major environmental pollutant, induced lung and l iver tumors 6-9 months after intraperitoneal injection of 0.7, 1.75 an d 3.5 mg FA into preweanling CD-1 mice. There was a dose-dependent inc rease in lung tumors with a maximum tumor incidence of nearly 45% and a maximum tumor multiplicity of 0.6-0.7 lung tumors/mouse. No signific ant difference was noted in lung tumors in the 6 and 9 month bioassays , although fewer tumors were consistently noted in mice treated with t he two lowest doses of FA. Indices of lung tumor incidence (ED50) and multiplicity (TM1.0) were similar for the two bioassays and ranged fro m 18.9-19.5 and 26.2-27.2 Amol respectively. Male mice had up to two t imes more lung tumors than females but these results were not statisti cally significant. Liver tumors (nodular hyperplasia) appeared only in FA-treated males but no dose-response relationship was evident. Howev er, liver tumors were observed in only 0-10% of the male mice in the 6 month treatment groups, but in 20-60% of the males in the 9 month gro ups. Because the CD-1 preweanling mouse responded to the weak lung tum origen FA, it is a viable, limited-term bioassay for measuring tumorig enicity of PAH and combustion emissions.