Cytochrome P450 system and heme synthesis enzymes activity in flounder liver as biomarkers of marine environments pollution

The total cytochrome P450 (CYP) levels, aryl hydrocarbon hydroxylase (AHH), aminopyrine N-demethylase (APND), 5-aminolevulinic acid synthase (ALA-S), and heme synthase (HEM-S) activities were analyzed in liver of flounder (Platichthys flesus) collected from urban and nonurban embayments of the Baltic Sea off Tallinn area to show the response of biomarkers to anthropogenic contaminants, especially carcinogenic PAHs, in marine environments. CYP, APND, ALA-S, and HEM-S values were higher in flounder from the urban sampling site. This correlates well with higher level of PAHs in tissues of flounder from the same site. AHH activities were quite high but have not shown statistically significant site difference although a slight tendency to be higher in flounder liver from the urban embayment was noticed. This study has confirmed the capability of AHH assay to demonstrate toxic contamination of marine environments in relation to the Baltic flounder as well as in previously tested species from other areas. Analyses of APND, ALA-S, and HEM-S activities are recommended as useful biomarkers for evaluation of general toxic load of environmental contamination.