Ethoxyresorufin-O-deethylase and porphyrin analysis in chicken embryo hepatocyte cultures with a fluorescence multiwell plate reader.

Rapid and sensitive methods for measuring ethoxyresorufin-O-deethylase (EROD) induction and total intracellular porphyrin accumulation in cultured chicken embryo hepatocytes exposed to polychlorinated biphenyls (PCBs) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are described. Cells were cultured in 48-well cell culture plates, and EROD assays were carried out directly within the wells. EROD activity and porphyrin concentrations were determined with a computer-operated fluorescence multiwell plate reader. Porphyrin and EROD assays could be carried out on the same plates or on separate plates. The assays allow one to obtain dose-response curves at rates that are approximately 100 times faster than conventional methods.