EVIDENCE FOR A TISSUE-SPECIFIC INDUCTION OF CUTANEOUS CYP2E1 BY DEXAMETHASONE

We studied in mouse the effect of topical application of dexamethasone or salicylic acid, on CYP2E1 and CYP3A expression (proteins and/or mR NA) in liver and skin. Dexamethasone was also administered by intraper itoneal injection. Topical application or intraperitoneal injection of dexamethasone increased cutaneous CYP2E1 (8 and 4-fold respectively) whereas the hepatic level of this isoform showed a slight decrease and hepatic CYP3A expression was increased (3-fold). Cutaneous CYP2E1 was increased (3-fold) after topical treatment by salicylic acid, This co mpound had no effect on hepatic CYP3A and CYP2E1 expression. Cutaneous CYP3A (protein and mRNA) was not detectable in all groups (control or treated animals). Dexamethasone and salicylic acid increased cutaneou s CYP2E1 mRNA level (2.5 and 1.4-fold respectively). In conclusion, de xamethasone and salicylic acid induced cutaneous CYP2E1 protein and mR NA level. Cutaneous CYP2E1 induction by dexamethasone is a tissue-spec ific process. (C) 1997 Academic Press.