CELLULAR-LOCALIZATION OF CYTOCHROME-P450 (CYP1A) INDUCTION AND HISTOLOGY IN ATLANTIC COD (GADUS-MORHUA L) AND EUROPEAN FLOUNDER (PLATICHTHYS-FLESUS) AFTER ENVIRONMENTAL EXPOSURE TO CONTAMINANTS BY CAGING IN SORFJORDEN, NORWAY

Immunohistochemical and histopathological studies were conducted in tw o marine teleosts, Atlantic cod (Gadus morhua) and European flounder ( Platichthys flesus), caged for three months on contaminated sediments in a Norwegian fjord, Cellular localization of CYP1A was analyzed immu nohistochemically in liver, intestine, heart, gill and kidney, as part of an extensive study that included a number of chemical and biologic al measurements. Both species exhibited marked CYP1A induction when ca ged at contaminated sites. CYP1A induction was observed in liver as we ll as in several extrahepatic organs, and with increased expression at the more contaminated sites, Staining was particularly strong in vasc ular en endothelium. Induction responses were also observed in epithel ial cells, including hepatocytes, biliary epithelial cells, mucosal ep ithelial cells in the intestine, and renal tubular epithelial cells, H istopathological examination of the liver did not reveal major cellula r abnormalities, The immunohistochemical data indicate a strong relati onship between CYP1A induction and exposure to sediment-associated ind ustrial contaminants (polycyclic aromatic hydrocarbons). Interesting s pecies differences in localization of CYP1A expression in Various cell types in cod and flounder were demonstrated immunohistochemically.