2.4.5. Ethoxyresorufin O-Deethylase (EROD) Activity

EROD (CYP1A) activity was measured according to the method adopted for the 24-well plate described by Ferreira et al. [18]. Briefly, after 24 h and 48 h of exposure to 0.1 µM, 0.5 µM, and 1 µM B[a]P, the medium was removed, and the cells washed once with cold PBS. EROD activity was measured by adding a EROD reaction mixture containing 1 mg/mL BSA, 5 μM 7-ethoxyresorufin (7-ER), and 0.5 mM NADPH and incubated for 30 min in the dark at 37 ± 1 °C. Fluorescence was measured at 560 nm excitation and 610 nm emission. EROD activity was calculated based on the resorufin standard curve obtained for each independent experiment. After EROD measurement, total protein concentration was determined in the same well by the Bradford method with BSA as a standard.