Superoxide radical: controversies, contradictions, and paradoxes.
The study of free radical biology has engendered a great deal of controversy and apparently conflicting observations, particularly with regard to the use of the antioxidant enzyme superoxide dismutase as a protective or therapeutic agent. Slowly, the reasons behind the confusion are beginning to emerge. The superoxide radical, O2.-, has a number of paradoxical physiological and pathophysiological roles. Several examples of the radical's schizophrenic behavior include its roles in bactericidal action versus inflammation, as a modulator of cell division versus malignant transformation and apoptosis, and as both an initiator and a terminator of lipid peroxidation.
McCord
J M
JM
Webb-Waring Institute, University of Colorado Health Sciences Center, Denver 80262, USA.
D000818:Animals; D017209:Apoptosis; D002455:Cell Division; D002471:Cell Transformation, Neoplastic; D007111:Immunity, Cellular; D008054:Lipid Peroxides / Q000378:metabolism; D010586:Phagocytes / Q000378:metabolism; D011817:Rabbits; D017382:Reactive Oxygen Species; D015427:Reperfusion Injury / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*
D008054:Lipid Peroxides; D017382:Reactive Oxygen Species; D013481:Superoxides; D013482:Superoxide Dismutase