[Biological evaluation of extracellular superoxide dismutase observed in a state of acute gastric mucosal lesions].

In the experimental stress ulcer models of guinea pig superoxide dismutase-like plasma substance increased in plasma. Upon chromatography on heparin-Sepharose, this substance was separated into three fractions; A, without affinity for heparin; B, with intermediate affinity for heparin; C, with relatively strong heparin affinity, and the fraction C was specifically increased by a stress and a heparin injection. Analysis by a polyacrylamide gel electrophoresis (PAGE) of the fraction C revealed SOD activity, whose molecular weight was 135 K in a native state. The fraction C seemed to be the same as extracellular superoxide dismutase (EC-SOD) reported by Marklund. Assuming to the releasing potency of heparin, the major part of EC-SOD in the vasculature was most likely located on endothelial-cell surface. A pathophysiological role of EC-SOD released into plasma seemed to be an indicator of endothelial-cell damage by free radicals of endothelial cells and polymorphonuclear neutrophils (PMNs).