Hepatic microsomal O-de-ethylases in cod (Gadus morhua): their induction by Aroclor 1254 but not by Aroclor 1016

1. The characteristics of hepatic ethoxycoumarin and ethoxyresorufin O-de-ethylases in juvenile cod (Gadus morhua) from the North Sea are described. 2. Feeding Aroclor 1254 to juvenile cod to produce liver concentrations of approx 900 microgram X g-1 (wet wt) induced ethoxycoumarin O-de-ethylase approx 30-fold, but had no effect on ethoxyresorufin O-deethylase activity. 3. Feeding Aroclor 1016 to juvenile cod to produce liver concentrations of approx 300 micrograms X g-1 (wet wt.) did not induce ethoxycoumarin O-de-ethylase activity.