Characteristics of the hepatic microsomal cytochrome P-450 system of the minke whale (Balaenoptera acutorostrata)

The whales are an interesting group in several aspects of science, including evolutionary biology, marine ecology and toxicology. Some of the whale species, including the minke whale, graze at the top of the food chains, where they become susceptible to the accumulation of marine pollutants ingested by organisms at lower levels. The northern stock of the minke whale grazes in Arctic waters in the summer, an area of increasing interest in the development of new oil fields. Studies on the metabolism, disposition and effects of xenobiotics in marine mammals are few. The only reports in the open literature so far have dealt with these questions in seals.^1–3 Although the marine mammals comprise a particularly interesting group in marine ecology and toxicology, no data have to our knowledge been presented on the xenobiotic metabolising enzyme systems of the whales. In this study, components of the microsomal cytochrome P-450 system were measured in liver samples from several females, one male, and two foetal minke whales, caught in the Norwegian whaling season of 1983. Because of the limited number of samples studied we have treated the samples individually and not performed any statistical analysis of the data. The trends discussed below must therefore be considered with this background.