Fig. 1. Ligand degradation by CYP1A1 as a negative feedback mechanism for AhR signaling. After a ligand binds AhR, AhR translocates to the nucleus and induces transcription of CYP1A1 mRNA and an increase in CYP1A1 enzymatic activity. This increased CYP1A1 degrades AhR ligands into inactive metabolites in order to terminate AhR signaling [15, 16].