RESPONSES OF THE MIXED-FUNCTION OXIDASE SYSTEM OF SOME BIVALVE AND GASTROPOD MOLLUSKS TO EXPOSURE TO POLYNUCLEAR AROMATIC AND OTHER HYDROCARBONS

The response of the cytochrome P-450 monooxygenase or mixed function oxidase (MFO) system to organic xenobiotics is of interest from the comparative viewpoint and in biological effects monitoring. We have studied the bivalves Mytilus edulis (mussel) and Cardium edule (cockle) and the gastropod Littorina littorea (periwinkle) exposed to hydrocarbons, experimentally or naturally in the field. The general trend of response in digestive gland microsomes was an increase in cytochrome P-450 content and NADPH-cytochrome c reductase (NADPH-CYTCRED) activity but no increase in benzo left bracket a right bracket pyrene hydrolyase (BPH) activity. Sex and seasonal interactions were evident. We conclude that aspects of the responses may be peculiar to the Mollusc and that NADPH-CTYCRED possibly offers potential for this phylogenetic group as a specific indicator of biological impact by organic pollution.