Investigations on benzyltoluenes. I. Induction of microsomal cytochrome P-450 and UDP-glucuronosyltransferase by tetrachlorobenzyltoluenes and by the condensate.

Tetrachlorobenzyltoluene (TCBT) (Ugilec 141) was investigated in induction experiments in male and female Wistar rats with long-term (50, 100 and 300 mg/kg p.o. daily for 28 days) and short-term administration (300 mg/kg once and 100 mg/kg daily for 4 days). The increase in total cytochrome P-450 did not exceed the factor of 1.9 compared to controls, while benzphetamine N-demethylase rose up to 3.5-fold the levels measured in controls, with very low induction of benzo(a)pyrene hydroxylase or ethoxyresorufin O-deethylase. Parallel investigations of UDP-glucuronosyltransferase showed induction of testosterone glucuronidation (1.7-fold). Administration (300 mg/kg body wt. once) of a pyrolysate of TCBT resulted in a marked increase in cytochrome P-450c dependent reactions (benzo(a)pyrene hydroxylase, ethoxyresorufin O-deethylase).