MODIFICATION OF HEPATIC DRUG-METABOLIZING-ENZYMES IN RAT FED NATURALLY-OCCURRING ALLYL SULFIDES

1. The effects of feeding allyl sulphides to rat (2000 ppm of the diet for 15 days) were investigated on various microsomal hepatic drug-metabolizing enzymes by their immunochemical detection and catalytic activity. 2. Allyl sulphides provoked a temporary dietary restriction, which enhanced the microsomal level of P450 and the activities of NADH-cytochrome c reductase and p-hydroxybiphenyl UDP-glucuronyltransferase (UDPGT 2), and lowered the activities of p-nitrophenol hydroxylase (PNPH), N-nitrosodimethylamine demethylase (NDMAD), laurate omega-hydroxylase (LAH) and glutathione S-transferase (GST). Therefore, pair-fed animals were used as a more relevant control for the dietary effects of allyl sulphides. 3. Diallyl sulphide (DAS) as well as diallyl disulphide (DADS) produced an enhancement of the microsomal level of P4501A2, 2B1/2 and 3A1/2, and epoxide hydrolase (EH) proteins, with an increase in the enzymatic activities they catalyse: ethoxyresorufin O-deethylase (EROD), aryl hydrocarbon hydroxylase (AHH), methoxyresorufin O-demethylase (MROD), ethoxycoumarin O-deethylase (FOOD), pentoxyresorufin O-depentylase (PROD), benzoxyresorufin O-debenzylase (BROD) and EH. Although P4502E1 proteins were lowered on treatment, NDMAD activity was not modified, and PNPH activity was even enhanced by allyl sulphides. Only DAS treatment raised erythromycin N-demethylase (ERDM) activity. 4. Both DAS and DADS increased the activity of GST and p-nitrophenol UDP-glucuronyltransferase (UDPGT 1), whereas UDPGT 2 activity was enhanced only by DAS.