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

Abstract

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.