title: 15-Hydroperoxyeicosapentaenoic acid inhibits arachidonic acid metabolism in rabbit platelets more potently than eicosapentaenoic acid.
abstract: The effect of 15-hydroperoxy-5,8,11,13,15-eicosapentaenoic acid (15-HPEPE), a hydroperoxy adduct of eicosapentaenoic acid (EPA), on the formation of 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE), thromboxane (TX) B2 and 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT) from exogenous arachidonic acid in washed rabbit platelets was examined. 15-HPEPE inhibited 12-HETE, TXB2 and HHT formation at concentrations ranging from 2 to 8 microM. The inhibitory effect of 15-HPEPE was dose-dependent (12-HETE, 16.0-82.9% inhibition; TXB2, 16.7-57.2% inhibition; HHT, 4.6-52.0% inhibition). EPA inhibited the production of these three metabolites, but the inhibitory effect was kept low (20-100 microM: 12-HETE, 8.3-31.1% inhibition; TXB2, 18.9-49.5% inhibition; HHT, 12.5-41.7% inhibition) as compared with 15-HPEPE. Experiments utilizing 15-hydroxy-5,8,11,13,15-eicosapentaenoic acid and hydroxyl radical scavengers (dimethyl sulfoxide and mannitol) revealed that 15-HPEPE exerted its effect in the form of the hydroperoxy adduct. These results suggest that 15-HPEPE has the potential to modulate the activities of the cyclo-oxygenase and 12-lipoxygenase in platelets. This may also be one convincing mechanism for the anti-thrombotic and anti-atherosclerotic actions of EPA.
authors.affiliation: Department of Hygienic Chemistry, Osaka University of Pharmaceutical Sciences, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Tsunomori
authors.forename: Y
authors.initials: Y
authors.lastname: Fujimoto
authors.forename: E
authors.initials: E
authors.lastname: Muta
authors.forename: H
authors.initials: H
authors.lastname: Nishida
authors.forename: S
authors.initials: S
authors.lastname: Sakuma
authors.forename: T
authors.initials: T
authors.lastname: Fujita
mesh_terms: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D000818:Animals; D016718:Arachidonic Acid / Q000097:blood / Q000378:metabolism*; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D015118:Eicosapentaenoic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D016166:Free Radical Scavengers / Q000378:metabolism / Q000494:pharmacology; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism; D017665:Hydroxyl Radical / Q000378:metabolism; D008084:Lipoxygenase / Q000378:metabolism; D008297:Male; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D011817:Rabbits; D013929:Thromboxane B2 / Q000378:metabolism
chemical_list: D005231:Fatty Acids, Unsaturated; D016166:Free Radical Scavengers; D006893:Hydroxyeicosatetraenoic Acids; D016718:Arachidonic Acid; D017665:Hydroxyl Radical; C008033:12-hydroxy-5,8,10-heptadecatrienoic acid; D013929:Thromboxane B2; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; C059164:15-hydroxy-5,8,11,13,17-eicosapentaenoic acid; C044353:15-hydroperoxy-5,8,11,14,17-eicosapentaenoic acid; D015118:Eicosapentaenoic Acid; D008084:Lipoxygenase; D011451:Prostaglandin-Endoperoxide Synthases