title: Alteration of platelet responses to metabolites of arachidonic acid by oral contraceptives.
abstract: The effects of oral contraceptive (OC) usage on platelet responsiveness to arachidonic acid metabolites was investigated. Platelets obtained from women who had been taking oral contraceptives for at least 3 months were compared with those of age-matched controls. Both the basal and prostacyclin (PGI2)-stimulated platelet cAMP levels were significantly lower in OC users than in non-users. There was no significant difference in the PGD2-stimulated cAMP levels between the two groups. Furthermore, platelet aggregability to U46619, a TXA2 agonist, was greatly enhanced by OCs. Our data suggests that OC usage can specifically enhance platelet responsiveness to TXA2 while suppressing platelet responsiveness to PGI2. Thus their overall effect would be a disruption of normal platelet responses in favour of thrombus formation.
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000097:blood; D000328:Adult; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism* / Q000494:pharmacology; D001792:Blood Platelets / Q000378:metabolism; D003276:Contraceptives, Oral / Q000494:pharmacology*; D003280:Contraceptives, Oral, Synthetic / Q000494:pharmacology*; D000242:Cyclic AMP / Q000097:blood; D011464:Epoprostenol / Q000494:pharmacology; D005260:Female; D006801:Humans; D010974:Platelet Aggregation / Q000187:drug effects*; D015230:Prostaglandin D2; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology; D011457:Prostaglandins D / Q000494:pharmacology; D013928:Thromboxane A2 / Q000096:biosynthesis / Q000494:pharmacology; D013929:Thromboxane B2 / Q000096:biosynthesis
chemical_list: D001095:Arachidonic Acids; D003276:Contraceptives, Oral; D003280:Contraceptives, Oral, Synthetic; D011450:Prostaglandin Endoperoxides, Synthetic; D011457:Prostaglandins D; D016718:Arachidonic Acid; D013929:Thromboxane B2; D013928:Thromboxane A2; D000244:Adenosine Diphosphate; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000255:Adenosine Triphosphate; D011464:Epoprostenol; D000242:Cyclic AMP; D015230:Prostaglandin D2