Page 617 - The Toxicology of Fishes

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Toxicity Resistance

Peter A. Van Veld and Diane E. Nacci

Fish populations in polluted streams, if not driven to local extinction,
may adapt to certain toxic substances over time.
Angus, 1983

CONTENTS
Introduction............................................................................................................................................598
Chemical Tolerance or Resistance to Toxic Effects....................................................................598
Variation in Chemical Response..................................................................................................599
Factors Influencing the Ability of Populations to Become Tolerant...........................................600
Environmental Contaminants That Produce Tolerance in Fish ............................................................601
Organochlorine Pesticides............................................................................................................601
Dioxin-Like Compounds..............................................................................................................602
Polycyclic Aromatic Hydrocarbons .............................................................................................603
Creosote........................................................................................................................................603
Metals ...........................................................................................................................................603
Biochemical Mechanisms and Models That Contribute to Our Understanding of Tolerance............. 604
Aryl Hydrocarbon Receptor.........................................................................................................604
Cytochrome P450.........................................................................................................................605
Glutathione S-Transferases and Other Phase II Enzymes...........................................................606
P-Glycoprotein .............................................................................................................................606
Metallothionein.............................................................................................................................606
Antioxidant Defense.....................................................................................................................607
Cancer as an Adaptive Response.................................................................................................607
Case Studies: Chemical-Specific Tolerance ..........................................................................................608
Tolerance to Organochlorine Pesticides.......................................................................................608
Tolerance to Metals......................................................................................................................609
Tolerance to Dioxin-Like Compounds.........................................................................................611
Other Evidence Involving CYP1A Suppression..........................................................................616
Tolerance to Creosote and Polycyclic Aromatic Hydrocarbons..................................................618
Costs Associated with Toxicity Resistance ...........................................................................................621
Effects of Contaminants on Specific Fitness Components .........................................................621
Population Genetic Effects of Contaminant Exposure................................................................622
Studies Involving Variation in Specific Genes ............................................................................624
Evolutionary and Ecological Impacts of Resistance...................................................................624
Summary and Conclusions....................................................................................................................626
Acknowledgment ...................................................................................................................................627
References..............................................................................................................................................628

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