Cytochrome P450 (CYP1A) induction in sea bream (Sparus Aurata) gills and liver following exposure to polychlorobiphenyls (PCBs)

Polychlorobiphenyls (PCBs) are a class of chlorinated organic compounds (Van den Berg et
al. 1998). PCB mixtures have several applications: in fluids for electrolytic capacitors and
transformers, in fluids for thermal exchange, in hydraulic fluids, in lubricating oil, and also
as additives in paints, pesticides and copier papers. PCBs can be divided into two groups:
dioxin-like PCB (DL-PCB) and non dioxin-like PCB (NDL-PCB). DL-PCBs are inducers
of cytochrome P4501A (Jonsson et al. 2007) and PCB126 is one of these inducers. DLPCB
toxicity is very high compared to NDL-PCB; in fact, these compounds are studied to
assure foodstuff, as they are considered as mutagens in animals and probably also in
humans (Knerr and Schrenk 2006; NTP 2006a; NTP 2006b). The concomitant presence of NDL-PCB and DL-PCB makes it difficult to detect the effects of NDL-PCB alone (Suh et
al. 2003; NTP 2006c; Smialowicz et al. 2008).The aim of this study was to investigate the
effects on cytochrome P4501A induction in the liver and gills of sea breams (Sparus
Aurata) after subacute exposure to PCB126 (a DL-PCB compound) or PCB153 (a NDLPCB
compound). We also evaluated the effects of exposure to a mixture of both PCBs to
investigate if an additive toxicity may occur.