title: Fish oil preparations rich in docosahexaenoic acid modify platelet responsiveness to prostaglandin-endoperoxide/thromboxane A2 receptor agonists.
abstract: The effects of daily dietary supplementation for 6 weeks with either 4.5 g eicosapentaenoic acid (EPA) and 3.35 g docosahexaenoic acid (DHA) (group I, EPA/DHA = 1.33) or 3.5 g EPA and 6.4 g DHA (group II, EPA/DHA = 0.54) on platelet responsiveness to the stable prostaglandin (PG)-endoperoxide analogue 9,11-dideoxy,9 alpha-11 alpha-methanoepoxy-PGF2 alpha (U 46619) were studied in healthy volunteers. Dose-response curves (DRC) of U 46619-induced platelet aggregation were analysed by computerized non-linear curve fitting. In group I, the concentration of U 46619 required for half-maximum platelet aggregation (EC50) remained unchanged, whereas the Hill coefficient decreased from 6.2 to 3.3 (P < 0.02). In group II, characterized by a high intake of DHA, a considerable increase of EC50 from 0.3 to 1.4 microM was found (P < 0.02). These results suggest different effects of EPA and DHA on the platelet thromboxane/endoperoxide-amplifying system. The considerable shift of the DRC in group II suggests a direct effect of DHA on the presentation of the endoperoxide receptor and/or post-receptoral events.
authors.affiliation: Medizinische Klinik und Poliklinik, Universität Tübingen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Scheurlen
authors.forename: M
authors.initials: M
authors.lastname: Kirchner
authors.forename: M R
authors.initials: MR
authors.lastname: Clemens
authors.forename: K
authors.initials: K
authors.lastname: Jaschonek
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000328:Adult; D001760:Bleeding Time; D001792:Blood Platelets / Q000187:drug effects*; D004281:Docosahexaenoic Acids / Q000032:analysis / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D015118:Eicosapentaenoic Acid / Q000032:analysis / Q000494:pharmacology*; D005395:Fish Oils / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology; D017482:Receptors, Thromboxane / Q000187:drug effects / Q000378:metabolism; D013928:Thromboxane A2 / Q000096:biosynthesis
chemical_list: D005395:Fish Oils; D011450:Prostaglandin Endoperoxides, Synthetic; D017482:Receptors, Thromboxane; D004281:Docosahexaenoic Acids; D013928:Thromboxane A2; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D015118:Eicosapentaenoic Acid