Issels R D, Fink R M, Lengfelder E
Gesellschaft fuer Strahlen- und Umweltforschung, Institut fuer Haematologie, Munich, W. Germany.
Free Radic Res Commun. 1986;2(1-2):7-18. doi: 10.3109/10715768609088051.
Generation and reactivity of superoxide (O2.-) and hydroxyl (OH.) radicals in enzymatic and radiolytic systems were investigated over the temperature range from 20 degrees-50 degrees C. The generation rate and reaction kinetics of both enzymatically and radiolytically produced superoxide radicals were determined by a cytochrome c reduction assay. For OH. radical reaction studies the degradation of hyaluronic acid was assayed. An increase in temperature leads to a greater reactivity of both radicals, but in the case of an enzymatic source a disproportionate increase in the rate of generation is observed. In the pulse radiolysis system, the reactivity of superoxide radicals was found to be stimulated 15-fold over the temperature range from 20 degrees C to 60 degrees C, although the activity of superoxide dismutase was only minimally increased (about 1.6-fold). The results are discussed with respect to the possible importance of active oxygen species to the biological effects of hyperthermia.
