title: Oxygen-radical-mediated lipid peroxidation and inhibition of ADP-induced platelet aggregation.
abstract: The effects of lipid peroxidation on ADP-induced aggregation of washed rat platelets were examined using a oxygen-radical-generating system consisting of H2O2 and ferrous ion. Lipid peroxidation was assessed by measurement of thiobarbituric acid-reactive substances (TBARS). Incubation of the platelets with various concentrations of H2O2 (2-10 mM) in the presence of 10 microM Fe2+ resulted in a decrease of the aggregating capacity and an increase of TBARS value, depending on the concentrations of H2O2. Addition of catalase (0.1 mg/ml) to the incubation medium containing 10 microM Fe2+ and 10 mM H2O2 effectively protected the aggregating capacity, but superoxide dismutase (0.1 mg/ml) did not protect H2O2/Fe(2+)-induced inhibition of the platelet aggregation. The results of kinetic studies on the platelet aggregation with varying ADP and Ca2+ concentrations suggested that treatment of the platelets with H2O2/Fe2+ causes decreases in the binding affinities of ADP and Ca2+ for the platelets. On the basis of these results, change in the aggregating capacity of the platelets by treatment with H2O2/Fe2+ is discussed in relation to lipid peroxidation.
authors.affiliation: Department of Biochemistry, School of Pharmacy, Hokuriku University, Ishikawa, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ohyashiki
authors.forename: M
authors.initials: M
authors.lastname: Kobayashi
authors.forename: K
authors.initials: K
authors.lastname: Matsui
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism; D005609:Free Radicals; D006861:Hydrogen Peroxide / Q000494:pharmacology; D066298:In Vitro Techniques; D007501:Iron / Q000494:pharmacology; D007700:Kinetics; D015227:Lipid Peroxidation; D008297:Male; D010100:Oxygen / Q000378:metabolism; D010974:Platelet Aggregation / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013858:Thiobarbiturates / Q000378:metabolism
chemical_list: D005609:Free Radicals; D013858:Thiobarbiturates; D000244:Adenosine Diphosphate; D006861:Hydrogen Peroxide; D007501:Iron; C029684:thiobarbituric acid; D010100:Oxygen