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Article
Relation among cytochrome p450, ah-active pcb congeners and dioxin equivalents in pipping black-crowned night-heron embryos
Article first published online: 21 OCT 2009
DOI: 10.1002/etc.5620131112
Copyright © 1994 SETAC
1552-8618/asset/cover.gif?v=1&s=f358d8623a91e6461314c56d177604eeef179c43 "Environmental Toxicology and Chemistry")
Additional Information
How to Cite
Rattner, B. A., Hatfield, J. S., Melancon, M. J., Custer, T. W. and Tillitt, D. E. (1994), Relation among cytochrome p450, ah-active pcb congeners and dioxin equivalents in pipping black-crowned night-heron embryos. Environmental Toxicology and Chemistry, 13: 1805–1812. doi: 10.1002/etc.5620131112
Publication History
- Issue published online: 21 OCT 2009
- Article first published online: 21 OCT 2009
- Manuscript Accepted: 15 APR 1994
- Manuscript Received: 29 NOV 1993
- Abstract
- References
- Cited By
Keywords:
- Biomonitoring;
- Enzyme induction;
- Nycticorax nycticorax;
- PCB congeners;
- Toxic equivalents
Abstract
Pipping black-crowned night-heron (Nycticorax nycticorax) embryos were collected from a relatively uncontaminated site (next to Chincoteague National Wildlife Refuge, VA) and three polluted sites (Cat Island, Green Bay, Lake Michigan, WI; Bair Island, San Francisco Bay, CA; West Marin Island, San Francisco Bay, CA). Hepatic cytochrome P450-associated monooxygenases and cytochrome P450 proteins, induced up to 85-fold relative to the reference site, were associated with concentrations of total polychlonrinated biphenyls (PCBs) and 11 PCB congeners that are presumed to express toxicity through the arylhydrocarbon (Ah) receptor Multiple regression revealed that up to 86% of the variation of cytochrome P450 measurements was accounted for by variation in the concentration of these PCB congeners. Toxic equivalents (TEQs) of sample extracts, predicted mathematically (summed product of PCB congener concentrations and toxic equivalency factors), and dioxin equivalents (TCDD-EQs), derived by bioassay (ethoxyresorufin-O-dealkylase activity of treated H4IIE rat hepatoma cells), were greatest in Cat Island samples. Cytochrome P450-associated monooxygenases and cytochrome P450 proteins were related to TEQs and TCDD-EQs; adjusted r2 often exceeded 0 5 for the relation among mathematically predicted TEQs and cytochrome P450 measurements. These data extend previous observations in heron embryos of an association between P450 and total PCB burdens to include Ah-active PCB congeners, and presumably other compounds, which interact similarly with the Ah receptor Benzyloxyresorufin O-dealkylase, ethoxyresorufin O-dealkylase, and cytochrome P450 1A appear to be the most reliable measures of exposure to Ah-active PCB congeners in black-crowned night-heron embryos. These findings provide further evidence that cytochrome P450-associated parameters have considerable value as a biomarker for assessing environmental contamination of wetlands