Comparative aspects of the disposition and metabolism of xenobiotics in fish and mammals.

The number of studies in aquatic toxicology has rapidly increased due to the importance of fish as a food source and also because of the increasing awareness of long-term health hazards of aquatic pollution of humans as well as to aquatic flora and fauna. The bioaccumulation and persistence of certain chemicals in fish have been studied for some time but with the characterization of an active hepatic mixed function oxidase system, comparable in many respects to that found in mammals, the role of metabolism in the disposition, toxicity, and persistence of certain chemicals can be studied. The recent observation that rainbow trout and their eggs are very sensitive to aflatoxin B1, a carcinogen that apparently must be activated to a chemically reactive intermediate to exert its effect, has led to the development of fish being considered appropriate animal models for toxicity testing. Since most predictive toxicology in the past has been restricted to nonaquatic species, this review has attempted to describe some of the similarities and dissimilarities between mammals and fish in terms of absorption, distribution, metabolism, and excretion of xenobiotics.