Cytochrome P450 and contaminant concentrations in nestling black-crowned night-herons and their interrelation with sibling embryos
- National Biological Service, Laurel, MD (United States). Patuxent Environmental Science Center
- National Biological Service, La Crosse, WI (United States). Upper Mississippi Science Center
- National Biological Service, Davis, CA (United States). California Pacific Science Center
Hepatic cytochrome P450-associated monooxygenase activities were measured in 11-d-old nestling black-crowned night-herons (Nycticorax nycticorax) collected from a reference site (next to Chincoteague National Wildlife Reguge, VA, USA) and three contaminated sites (Cat Island, Green Bay, WI, USA; Bair Island, San Francisco Bay, CA, USA; and West Marin Island, San Francisco Bay, CA, USA). Arylhydrocarbon hydroxylase and benzyloxyresorufin-O-dealkylase activities of nestlings from contaminated sites were only slightly elevated (less than threefold) compared with the reference site. Organochlorine pesticide and total polychlorinated biphenyl (PCB) concentrations in nestlings were greatest at contaminated sites, although much lower than found in concurrently collected eggs and pipping embryos. Pollutant concentrations of nestlings were rarely associated with monooxygenase activity. In contrast, concurrently collected pipping heron embryos (often siblings of the nestlings) exhibited pronounced monooxygenase induction (means at contaminated sites were elevated up to sevenfold and values of some embryos exceeded 25-fold induction). Furthermore, monooxygenase activity of pipping embryos was significantly correlated with total PCBs, arylhydrocarbon receptor-active PCB congeners, and toxic equivalents. The modest monooxygenase responses of heron nestlings suggest that this biomarker may have only limited value during this rapid-growth life stage.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 264318
- Journal Information:
- Environmental Toxicology and Chemistry, Vol. 15, Issue 5; Other Information: PBD: May 1996
- Country of Publication:
- United States
- Language:
- English
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