SUPEROXIDE RADICAL - CONTROVERSIES, CONTRADICTIONS, AND PARADOXES

The study of free radical biology has engendered a great deal of contr oversy and apparently conflicting observations, particularly with rega rd to the use of the antioxidant enzyme superoxide dismutase as a prot ective or therapeutic agent. Slowly, the reasons behind the confusion are beginning to emerge. The superoxide radical, O-2(-), has a number of paradoxical physiological end pathophysiological roles. Several exa mples of the radical's schizophrenic behavior include its roles in bac tericidal action versus inflammation, as a modulator of cell division versus malignant transformation and apoptosis, and as both an initiato r and a terminator of lipid peroxidation.