Male C57BL/6 × C3H/anf F1 mice were either untreated or fed 3,5-dichloro(N-1,1-dimethyl-2-propynyl)benzamide, a chlorinated hydrocarbon pesticide, for 12, 18 or 24 months. Mice in the highest dose group showed evidence of chronic liver toxicity including necrosis and an increased incidence of tumors diagnosed malignant by histological assessment. The increase in malignant tumors was not accompanied by an increased mortality. Glucose-6-phosphatase and alkaline phosphatase were good markers for mouse hepatic nodules. γ-Glutamyl transpeptidase was not a good marker and was irregularly present in these lesions. Nodules also had a relative decrease in aryl hydrocarbon hydroxylase activity and an increase in the K form of the glycolytic enzyme, pyruvate kinase. Treatment type, as well as nodular morphology, had an effect on enzyme activity in the case of each of the markers.
This work was supported in part by a grant from Rohm and Haas Co., Spring House, Pa., and by Grant ES 00597 from the National Institute of Environmental Health Sciences.