Apparent cytochrome P-450 induction as an indication of exposure to environmental chemicals the flounder Platichthys flesus

Flounder Platichthys flesus from a pollution gradient in Langesundfjord, Norway, and from experimental exposures to diesel oil in mesocosm basins, were analyzed during the GEEP Workshop for evidence of specific cytochrome P-450 induction.Ethoxyresomfin 0-de-ethylase (EROD) activity and the content of microsomal cytochrome P-450 in liver were positively correlated with the field pollution gradient, as indicated by residues of PAH and PCB in mussels at the 4 sites.Monoclonal antibody 1-12-3 to the PAH-and PCB-inducible scup P-450 isozyme (P-450E) recognized a single protein band in P. flesus liver microsomes.The amount of this protein correlated positively with levels of EROD activity and microsomal P-450 content in the field-sampled fish.By contrast, fish from control and treated mesocosm basins all possessed relatively low levels of EROD activity and immunodetected protein.Levels of high molecular weight PAH known to induce teleost P-450 were likewise low in these basins, although there was a high content of other aromatics.We conclude that both EROD activity and levels of the P. flesus counterpart to P-450E indicate induction by environmental chemicals in P. flesus from Langesundfjord.