Biotransformation of chemicals by fish: an overview

Evidence accumulated in recent years indicates that many species of fish possess most of the hepatic drug-metabolizing enzyme activities that have been demonstrated to exist in higher vertebrates. Although much of the early work with fish involved in vitro studies, it is now apparent that fish are capable of many phase I and II biotransformation reactions in vivo as well, but the rate and pathways for a given compound may vary widely among species of fish. In several instances, it has been demonstrated that the rate of biotransformation of certain compounds is appreciable. Biotransformation may be important in protecting fish from the toxic effects of certain chemicals by converting them to less biologically active chemicals. On the other hand, evidence is mounting that certain species of fish can react in such a way in vivo so as to produce active carcinogens from chemicals which are not themselves carcinogenic.