Transcriptional effects of nonylphenol, bisphenol A and PBDE-47 in liver of juvenile Atlantic cod (Gadus morhua)

The transcriptional levels of 10 genes were quantified in liver of Atlantic cod exposed to environmental relevant concentrations of three model toxicants; two alkylphenols (30 mu g/L nonylphenol (NP) and 50 mu g/L bisphenol A (BPA)) and one brominated flame-retardant congener (5 mu g/L PBDE-47). The fish were exposed to the toxicants for 3 weeks, with n = 6 in each group (a total of 24 fish were used). NP exposure produced a significant reduction of five CYPs genes (CYP1A (P < 0.01). CYP2C33-like (P < 0.001), CYP2Y3 (P < 0.001), CYP2P1-like (P < 0.01) and CYP3C1-like (P < 0.01)). A significant reduction was also seen for three CYPs after BPA exposure (CYP2C33-like, CYP2Y3 and CYP3C1-like (P < 0.01 for all)). PBDE-47 exposure produced a significant reduction of CYP1A, CYP2C33-like and CYP3C1-like (P < 0.05 for all). The genes encoding Phase II enzymes responded in a different manner; NP exposure resulted in a 4.6-fold increase of GST pi (P < 0.001), whereas BPA exposure gave no effects on these enzyme genes. PBDE-47 exposure resulted in a 3.3-fold reduction of UGT (P < 0.05). No effects were seen on the antioxidant genes GSH-Px and GR for any of the three toxicants. Thus, all three toxicants seem to down regulate several CYPs, giving rise to distinct mRNA expression patterns suggesting that these toxicants act on the same receptors or via the same pathways. (C) 2008 Elsevier Ltd. All rights reserved.