| Abstract: | The abilities of chemically generated hydroxyl radical (OH), superoxide anion (O?) and hydrogen peroxide (H2O2) to degrade rat myocardial membrane phospholipids previously lableed with [1 -14C]arachidonic acid were studied. HO and H2O2 but not O2??, caused the degradation of phospha-tidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI). With OH' and H2O2, the loss of radiolable in PC was accompanied by an increase in the radiolabel of lysophosphatidylcholine (LPC), but not in that of free fatty acid (FFA). These results suggest the hydrolysis of l-oxygen ester bond of PC by HO' and that H2O2 and that HO' and H2O2, but not O?, are detrimental to the structure and function of membrane phospholipids. However, since μM amounts of HO' and mM amounts of H2O2 were necessary to affect the membrane phospholipids, it is likely that in the reprefused myocardium only HO', but not H2O2, may directly cause the breakdown of membrane phospholipids. |
