Activities and toxicological significance of hepatic microsomal enzymes of the kestrel (Falco tinnunculus) and sparrowhawk (Accipiter nisus).

Activities of hepatic microsomal monooxygenase and epoxide hydrolase in sparrowhawks and kestrels were determined using organochlorine substrates. Monooxygenase activities were low in the kestrel and very low in the sparrowhawk compared to those in the male rat, down to environmentally realistic substrate concentrations. Epoxide hydrolase activities were very low in both species. These activities are discussed in relation to feeding ecology and susceptibility to organochlorine pollutants.