CYP1A and metallothionein expression in the hepatopancreas of Merluccius merluccius and Mullus barbatus from the Adriatic Sea

The enzyme CYP1A is an established biomarker of fish exposure to polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). The metallothioneins (MT), a family of Cys-rich proteins, bind a wide range of metals and participate in their metabolism. The aim of the study was to examine the correlation between CYP1A and MT expression in commercially important fish species Mullus barbatus and Merluccius merluccius and contaminants (PAHs, PCBs, toxic metals) in seawater and sediment from three localities with different level of contamination in the Adriatic Sea in winter, i.e., Platamuni, Valdanos and the port of Bar. The relative concentration of CYP1A was the highest in both fish species from Bar. Increased concentrations of PCBs in the seawater were observed only in Bar. A species-specific higher increase in the protein concentration of CYP1A was observed in Mullus barbatus compared to Merluccius merluccius. The levels of MT were the highest in Merluccius merluccius from Bar and in Mullus barbatus from Valdanos. The induction of MT correlated with the elevated concentrations of Cu and Pb determined by chemical analysis of the seawater from Bar and Valdanos, respectively. According to the chemical analysis of the seawater and the biological response of the fish, the Platamuni locality exhibited the lowest level of contamination.