tokens: 5 , 5 , 10 and 15 mg / kg , body weight ) for 5 days was found to produce a dose - dependent increase in the activity of P450 dependent 7 - ethoxyresorufin - O - deethylase ( EROD ), 7 - pentoxyresorufin - O - dealkylase ( PROD ) and N-nitrosodimethylamine demethylase ( NDMA - d ) in rat brain and liver .