In order to study expression levels of cytochrome P450 1A (CYP1A) and COX2b, quantitative real-time RT-PCR (RT-qPCR) analysis was carried out [57 (link)]. Total RNA was extracted from larval zebrafish at 55 hpf with TRI-reagent (Sigma-Aldrich, St. Louis, MO). cDNA was prepared from total RNA with ReverTra Ace qPCR RT Kit (Toyobo, Osaka, Japan). qRT-PCR analysis was performed in Real-Time PCR Detector (LightCycler 96: Roche Life Science, Penzberg, Germany) using Thunderbird qPCR mix containing SYBR Green (Toyobo).