Hepatic biotransformation in the buzzard (Buteo buteo) and the Japanese quail (Coturnix coturnix): effect of PCBs.

Hepatic biotransformation was studied in microsomal (cytochrome P-450-dependent monooxygenase activities) and cytosolic (glutathione S-transferase activities) fractions from Japanese quail (Coturnix coturnix) and buzzard (Buteo buteo). Monooxygenase activities were not very different apart from a high 7-ethoxycoumarin de-ethylase activity in quail as compared to buzzard. Glutathione S-transferase activities were higher in quail than in buzzard. DP5 (a commercial mixture of PCBs containing 50% chlorine) produced a marked increase in monooxygenase activity from quail liver. In contrast, no induction was found in buzzard under the same conditions. Glutathione S-transferase activities were not modified in both species.