title: The influence of triiodothyronine (T3) and inducers on hepatic drug metabolism in rats of different ages.
abstract: After a 3-day treatment with T3 the ethylmorphine N-demethylation rate was diminished in 10- to 60-day-old rats, whereas the ethoxycoumarin O-deethylation rate was distinctly enhanced in some age-groups, particularly in 33-day-old rats. P-450 concentration was decreased in young rats and not changed in 60-day-old ones. Phenobarbital administration enhanced the rate of both reactions and P-450 concentration in all age-groups. This treatment significantly attenuated the T3 effects on P-450 concentration and ethylmorphine N-demethylation. beta-Naphthoflavone induced ethoxycoumarin O-deethylation and P-450 concentration in all age-groups. Compared with non-induced animals, the T3 effects on ethoxycoumarin O-deethylation (increase) and ethylmorphine N-demethylation (decrease) were more distinct, whereas P-450 concentration was scarcely influenced by T3. Age-differences in T3 actions were generally diminished by inducers.
mesh_terms: D000367:Age Factors; D000818:Animals; D001571:Benzoflavones / Q000494:pharmacology; D001711:Biotransformation / Q000187:drug effects; D003374:Coumarins / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D005036:Ethylmorphine / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014284:Triiodothyronine / Q000494:pharmacology*; D019324:beta-Naphthoflavone
chemical_list: D001571:Benzoflavones; D003374:Coumarins; D014284:Triiodothyronine; C017299:7-ethoxycoumarin; D019324:beta-Naphthoflavone; D003577:Cytochrome P-450 Enzyme System; D005036:Ethylmorphine; D010634:Phenobarbital