AGE-RELATED CHANGES IN METABOLISM OF DIETHOFENCARB : RELATIONSHIP BETWEEN METABOLISM IN RAT AND HEPATIC DRUG-METABOLIZING ENZYME ACTIVITIES

1. Age-related changes in metabolism of diethofencarb (DFC) (isopropyl-1, 4-diethoxycarbanilate) and hepatic drug-metabolizing enzyme activities were studied in male Sprague-Dawley rats aged 2, 8, 16 and 21 months. 2.3. Analysis of urinary metabolites showed that deethylation of 14C-DFC was constant for all age groups; however, sulphation and acetylation significantly decreased, and glucuronidation increased, with age.4. Hepatic PAPS-sulphotransferase and acetyl-CoA: N-acetyltransferase in DFC metabolism significantly decreased with age, whereas no significant effects of ageing on O-deethylase and UDP-glucuronyltransferase were observed.5. Results show that age-related differences in the ratios of urinary metabolites of DFC resulted to some extent from changes in the hepatic drug-metabolizing enzyme activities.