Free radical-induced damage of cardiac sarcolemma (SL) and activity loss of beta-receptor adenylate cyclase system (beta-RAS). A comparison of the time courses.

In vitro studies have demonstrated that free radicals generated by Fe2+/Vit. C alter the beta-RAS function. SH-oxidation, peroxidation of sarcolemmal lipids and reaction of aldehydes (formed by lipid peroxidation) with the beta-RAS may contribute to this effect. In order to clarify the role of these reactions in respect to their ability to alter the beta-RAS function the time course of SH-oxidation, lipid peroxidation and formation of aldehyde reaction products has been studied. As result it is shown that SH-oxidation is nearly completed within 5 minutes and lipid peroxidation within 30 minutes after exposure to Fe2+/Vit. C. During this time period there was only a very small amount of aldehyde reaction products detectable. Therefore SH-oxidation and/or lipid peroxidation should be responsible for the activity loss of the beta-RAS.