Alterations in lipid peroxidation of thrombin-stimulated rat platelets treated with beta-adrenoceptor blocking drugs.

Thrombin-stimulated formation of malondialdehyde in isolated rat platelets was time- and dose-dependent and occurred in parallel with thromboxane B2 production and platelet aggregation. beta-Adrenoceptor blocking drugs inhibited thrombin-stimulated malondialdehyde formation according to their liposolubility in the rank order of potency: atenolol < practolol < oxprenolol < metipranolol approximately alprenolol approximately propranolol. In platelets pretreated with beta-blockers and stimulated with thrombin, a positive correlation was found between malondialdehyde formation and inhibition of aggregation, arachidonic acid liberation from membrane phospholipids as well as thromboxane production. Measurement of malondialdehyde was shown to be an indicator for the arachidonic acid pathway in stimulated and inhibited isolated platelets.