CHARACTERIZATION OF RAT HEPATIC CYTOCHROME P-450 ACTIVITIES FOLLOWING INHALATION EXPOSURE TO p-CHLOROBENZOTRIFLUORIDE

p-Chlorobenzotrifluoride (PCBTF), an intermediate in the synthesis of some herbicides, is currently being evaluated as an industrial solvent. The neurotoxicity of PCBTF was evaluated in a 90-day inhalation study in male and female Sprague-Dawley rats exposed for 6 h/day to target concentrations of 0, 10, 50, and 250 ppm PCBTF. Following exposure for 90 days, the livers were weighed, frozen, and microsomal fractions prepared to assess cytochrome P-450 (CYP450) content and activities. A significant increase in liver weight and CYP450 content in female rats was observed in the high exposure group (250 ppm), while the increase in males was not found to be statistically significant. 7-Ethyoxyresorufin O -deethylase (EROD), a measure of CYP1A1 activity, and acetanilide and phenacetin metabolism, a measure of CYP1A2 activity, were increased about twofold in both males and females at the high exposure level (250 ppm). Pentoxyresorufin O dealkylase (PROD) and benzyloxyresorufin O -dealkylase (BROD), a measure of C...