Responses of microsomal NADPH-cytochrome c reductase activity and cytochrome P-450 in digestive glands of Mytilus edulis and Littorina littorea to environmental and experimental exposure to pollutants

Abstract

Digestive gland microsomal components were measured during the GEEP Workshop in mussels Mytilus edulis and periwinkles Littorina littorea exposed to different levels of chemical contaminants in an experimental facility (diesel oivcopper mixture) and along a field pollution gradient in Langesundfjord, Norway. Cytochrome P-450 content increased in mussels and periwinkles with experimental exposure and was elevated in mussels from some of the more contaminated field sites. Increases in P-450 content were accompanied by a blue shift in the P-450 A,, suggesting isoenzyme synthesis. NADPH-cytochrome c (P-450) reductase activity increased in mussels and periwinkles with experimental exposure but showed only decreases in the field. The '418' peak of the P-450 carbon monoxide difference spectrum increased in mussels and periwinkles with both experimental and field contaminant exposure. It is concluded that mussels were affected by organic chemical contamination, and to an extent increasingly so with increasing contamination, but that apphcation of these methods in environmental monitoring is limited by a lack of understanding of the basic nature and function of the molluscan MFO system.