Evaluation of the promotion potential of chlorotrifluoroethylene trimer acid in male Sprague-Dawley rats.

The promoting effect of chlorotrifluoroethylene trimer acid (TRA), a metabolite of the 6-carbon oligomer of Halocarbon 3.1 oil, was investigated using a bioassay designed to detect enzyme-altered foci. These oligomers, as well as their carboxylic acid metabolites, have been shown to cause hepatomegaly and an increased rate of hepatic peroxisomal fatty acid beta-oxidation following administration by oral and inhalation routes. Groups of 2/3 partially hepatectomized male Sprague-Dawley rats were initiated with a single dose of diethylnitrosamine (10 mg/kg). Two weeks later phenobarbital (0.5% in the drinking water) was provided to animals in the positive control group. At the same time, three other groups received an initial dose of TRA by intraperitoneal injection (98, 9.8 and 0.98 mg/kg). Biweekly intraperitoneal injections of TRA (12.3, 1.2, and 0.12 mg/kg) were continued for 9 months. Quantitative sterological analysis revealed that TRA exposure resulted in a significant dose-dependent increase in the number of gamma-glutamyltranspeptidase-positive foci.