Reactive oxygen species, antioxidants, and the mammalian thioredoxin system1 1This review is based on the licentiate thesis “Thioredoxin reductase—interactions with the redox active compounds 1-chloro-2,4-dinitrobenzene and lipoic acid” by Jonas Nordberg, 2001, Karolinska Institute, Stockholm, ISBN 91-631-1064-4.