P-glycoprotein and CYP1A protein expression patterns in Nile tilapia (Oreochromis niloticus) tissues after waterborne exposure to benzo(a)pyrene (BaP).

The protein levels and tissue distribution patterns of P-glycoprotein (Pgp) and cytochrome P450 (CYP1A) were investigated in Nile tilapia (Oreochromis niloticus) after waterborne exposure to different benzo(a)pyrene (BaP) concentrations, using immunochemical approaches. The Pgp mammalian monoclonal antibody (mAb) C219 cross reacted with a ∼170kDa protein, almost exclusively localized to the bile canaliculi, while probing with the Pgp mammalian mAb C494, resulted in a positive reaction in liver, gills and intestine of Nile tilapia and covered a wider set of cell types. Levels of Pgp expression were not altered after in vivo exposure to BaP. CYP1A, detected with the mAb C10-7, reacted positively in liver, gills and intestine and followed a BaP dose-dependent fold induction. Taken together, these results indicate that CYP1A is involved in BaP metabolism in liver, gills and intestine, however, further studies are needed to elucidate the possible interaction of the efflux protein Pgp with BaP and/or its metabolites.