Page 293 - The Toxicology of Fishes

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Reactive Oxygen Species and Oxidative Stress

Richard T. Di Giulio and Joel N. Meyer

CONTENTS
Introduction............................................................................................................................................274
Reactive Oxygen Species and Free Radicals........................................................................................274
Endogenous Cellular Sources of Reactive Oxygen Species.................................................................276
Antioxidant Defenses.............................................................................................................................278
Antioxidant Enzyme Systems......................................................................................................278
Superoxide Dismutases.......................................................................................................278
Catalases .............................................................................................................................279
Glutathione Peroxidases and Transferases.........................................................................279
Glutathione: Synthesis and Maintenance...........................................................................280
Quinone Reductases............................................................................................................282
Low-Molecular-Weight Antioxidants...........................................................................................283
Ascorbic Acid (Vitamin C).................................................................................................283
Vitamin E............................................................................................................................285
Carotenoids .........................................................................................................................285
Other Antioxidants..............................................................................................................285
Reactive Oxygen Species and Gene Expression...................................................................................286
ROS-Mediated Modulation of Gene Expression in Prokaryotes................................................286
Overview of ROS-Mediated Modulation of Gene Expression in Eukaryotes............................ 287
Effects of ROS on Transcription Factors.....................................................................................287
Effects of ROS on mRNA Expression.........................................................................................288
Antioxidant Response Element (ARE)-Mediated Gene Regulation...........................................288
ROS-Mediated Modulation of Gene Expression: Summary.......................................................291
Deleterious Cellular Effects of Reactive Oxygen Species....................................................................291
Lipid Peroxidation........................................................................................................................292
Protein Oxidations........................................................................................................................293
Redox Status and Energetics........................................................................................................294
Deleterious Organismal Effects of Reactive Oxygen Species..............................................................294
Diseases Associated with Oxidative Stress..................................................................................295
Aging and Oxidative Stress .........................................................................................................295
Chemicals and Oxidative Stress...................................................................................................295
Natural Products .................................................................................................................296
Drugs...................................................................................................................................296
Environmental Pollutants....................................................................................................296
Mechanisms of Chemical-Mediated Oxidative Stress ..........................................................................298
Enhanced ROS Production...........................................................................................................298
Redox Cycling ....................................................................................................................298
Uncoupling or Inhibition of Electron Transport................................................................298
Photosensitization ...............................................................................................................300
Diminished Antioxidant Defense.................................................................................................300

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