title: Cytochromes P450, P420 & mixed-function oxidases as biomarkers of polychlorinated biphenyl (PCB) exposure in harbour seals (Phoca vitulina).
abstract: Hepatic microsomal cytochrome P450, EROD and ECOD activity were investigated as biomarkers of PCB exposure in harbour seals (Phoca vitulina). Due to the difficulty of obtaining undegraded seal liver samples, standard spectrophotometric methodology was adapted to investigate P420 (degraded P450) as a PCB biomarker with partially degraded samples. Total PCB burdens in both blubber and liver had positive correlations with P450, P420 and MFO activity levels. The use of P420 biomarkers in this study supports the inclusion of samples from by-caught marine mammals for future biomonitoring studies. P450 isozymes CYP1A (P4501A) and CYP2B (P4502B) in conjunction with MFO activity were investigated as "specific" biomarkers of PCB exposure. They were found to reliably reflect levels of [MC] and [PB]-type PCB exposure in harbour seal liver.
authors.affiliation: Department of Biological & Chemical Sciences, University of Essex, Colchester, UK.
authors.forename: G M
authors.initials: GM
authors.lastname: Troisi
authors.forename: C F
authors.initials: CF
authors.lastname: Mason
mesh_terms: D000273:Adipose Tissue / Q000201:enzymology; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D001822:Body Burden; D019363:Cytochrome P-450 CYP1A1 / Q000032:analysis; D019362:Cytochrome P-450 CYP2B1 / Q000032:analysis; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis*; D003580:Cytochromes / Q000032:analysis*; D017753:Ecosystem; D008099:Liver / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000032:analysis*; D011078:Polychlorinated Biphenyls / Q000633:toxicity*; D046048:Seals, Earless / Q000378:metabolism*; D012623:Seawater / Q000032:analysis; D006113:United Kingdom; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D015415:Biomarkers; D003580:Cytochromes; D014874:Water Pollutants, Chemical; C013464:cytochrome P420; D003577:Cytochrome P-450 Enzyme System; D011078:Polychlorinated Biphenyls; D006899:Mixed Function Oxygenases; D019363:Cytochrome P-450 CYP1A1; D019362:Cytochrome P-450 CYP2B1