title: Hepatic cytochrome P450 activity and pollutant concentrations in paradise shelducks and southern black-backed gulls in the South Island of New Zealand.
abstract: Cytochrome P450 (CYP) enzymes catalyse the oxidative metabolism of various xenobiotics including environmental pollutants. We investigated liver microsomal CYP marker activities in 60 paradise shelducks (Tadorna variegata; herbivore) and 77 southern black-backed gulls (Larus dominicanus; omnivore) collected at three sites with putatively different levels of pollution in the South Island of New Zealand. Ethoxyresorufin O-deethylase (EROD) activity was high in birds at an urban landfill site compared to those at a relatively pristine and an agricultural site. Analysis of p-nitrophenol hydroxylase and erythromycin demethylase activities indicated the presence of two additional CYP isoforms in shelducks but no additional form in gulls. Total polychlorinated biphenyl (PCB) concentrations (ranges: shelducks, 0.073-6.2; gulls, 8.2-330 ng/g wet weight) were high in landfill samples suggesting a link to EROD induction and, in landfill shelducks, EROD was independently associated with Hg and Pb concentration. PCB congener-specific assessments indicated the metabolism of at least two congeners (#28 and #74) is induced in shelducks. DDE concentrations (ranges: shelducks, 0.85-320; gulls, 44-4800 ng/g) were high in birds at the landfill and agricultural sites. Body weight tended to be lower in landfill birds, but whether this reflects the greater energetic demands of pollutant detoxification remains to be investigated.
authors.affiliation: School of Pharmacy, University of Otago, P.O. Box 913, Dunedin, New Zealand. mihoko.numata@stonebow.otago.ac.nz.
authors.forename: Mihoko
authors.initials: M
authors.lastname: Numata
authors.forename: J Paul
authors.initials: JP
authors.lastname: Fawcett
authors.forename: Dorothy J
authors.initials: DJ
authors.lastname: Saville
authors.forename: Rhonda J
authors.initials: RJ
authors.lastname: Rosengren
mesh_terms: D000818:Animals; D046091:Charadriiformes / Q000378:metabolism*; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism*; D004372:Ducks / Q000378:metabolism*; D004785:Environmental Pollutants / Q000009:adverse effects* / Q000737:chemistry; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D019216:Metals, Heavy / Q000737:chemistry; D009520:New Zealand; D011078:Polychlorinated Biphenyls / Q000737:chemistry
chemical_list: D004785:Environmental Pollutants; D006843:Hydrocarbons, Chlorinated; D019216:Metals, Heavy; D011078:Polychlorinated Biphenyls; D019363:Cytochrome P-450 CYP1A1