Murine Cyp 1a-1 induction in mouse hepatoma Hepa-$k$/C7 cells by myristicin

Abstract

Mouse hepatoma Hepa-1c1c7 (Hepa-l) cells were treated with myristicin to assess the role of myristicin in the process of Cyp1a-1 induction. Treatment of Hepa-l cells with myristicin increased Cyp1a-1 transcription in a dose-dependent manner as shown by analysis of 7-ethoxyresorufin O-deethylase activity, Cypla-1 protein level, and Cypla-1 mRNA. Myristicin, however, did not competitively displace [H-3]2,3,7,8-tetrachlorodibenzo-p-dioxin from the Hepa-l cytosolic aryl hydrocarbon (Ah) receptor in a competitive Ah receptor binding analysis using sucrose density gradient sedimentation and did not affect formation of DNA-protein complexes between the Ah receptor and its DRE target in a gel mobility shift assay using oligonucleotides corresponding to DRE 3 of the Cyp1a-1. These results suggest that the induction of Cyp1a-1 gene expression by myristicin in Hepa-l cells might occur through an Ah receptor-independent pathway. (C) 1997 Academic Press.