Peroxide treatment changes activity of non specific esterase in vascular endothelium of isolated pig aorta in vitro

The effect of hydrogen peroxide on certain enzymes contained in endothelial cells was investigated in vitro. Specifically in this study the influence of hydrogen peroxide on the non-specific esterase activity in endothelial cells of the perfused pig aorta was examined. We perfused an isolated segment of the pig aorta for 10 h and added 5, 10, 12, 15 ml 10% hydrogen peroxide to 100 ml perfused medium. In unperfused pig aorta 99.34% of the endothelial cells reacted positive. After 10 h of perfusion without hydrogen peroxide administration 93.25% endothelial cells still showed positive enzyme reactivity. In presence of hydrogen peroxide in the perfusion medium the activity of non-specific esterase was progressively inhibited, finally causing complete inactivation.