Combined action of phenobarbital and dexamethasone on the activity of rat liver P450 system.

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Monostory K, Vereczkey L

Combined action of phenobarbital and dexamethasone on the activity of rat liver P450 system.

Acta Pharm Hung. 1993 Sep;63(5):296-300.

PubMed ID

8249615 [ View in PubMed

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Abstract

Phenobarbital and dexamethasone are potent inducers of the same cytochrome P450 form, CYP3A1, but the mechanism of action is not quite clear. If the mechanism of induction by phenobarbital and dexamethasone is different, additive effect may be observed in the specific activities of CYP3A1: ethylmorphine or aminopyrine N-demethylation of liver microsomes from rats treated with phenobarbital and dexamethasone in combination. The results of recent work could not display differences in CYP3A1 activities between the groups of animals single-administered and coadministered with phenobarbital and dexamethasone. However, p-nitrophenol hydroxylation surprisingly increased threefold as a result of double induction. 3-amino-1,2,4-triazole inhibition study shows that CYP2E1 is responsible for 60% of enhanced p-nitrophenol hydroxylase activity, but the residual 40% indicates the participation of other isoenzyme(s).

DrugBank Data that Cites this Article

Drug Enzymes

Drug	Enzyme	Kind	Organism	Pharmacological Action	Actions
Dexamethasone	Cytochrome P450 2E1	Protein	Humans	Unknown	Inducer	Details
Dexamethasone acetate	Cytochrome P450 2E1	Protein	Humans	Unknown	Inducer	Details