title: Factor VIII and human platelet aggregation. II. Characteristics of aggregation of human platelets by bovine factor VIII.
abstract: Bovine factor VIII aggregates human platelets either in a strong single wave at high concentration (10 mug/ml platelet suspension) or in two waves at low concentration (0.2-I mug/ml). The strong single wave of aggregation is not associated with release of [14C]serotonin or beta-glucuronidase; the high concentration does not induce retraction of reptilase-clotted platelet-rich plasma. Wtih the low concentration, relase of [14C]serotonin is observed just prior to the onset of the second wave of aggregation; release of beta-glucuronidase does not occur at any moment. The low concentration of bovine factor VIII induces moderate retraction of reptilase-clotted platelet-clotted platelet-rich plasma, which is inhibited by acetylsalicylic acid, indomethacin and apyrase, indicating that it is a consequence of release of platelet adenosine-5'-diphosphate. It has previously been suggested tht carbohydrate groups are involved in the human platelet-bovine factor VIII interaction, since galactose oxidase and periodate oxidation abolish the platelet aggregating activity of bovine factor VIII. The present study shows that these oxidizing substances also induce a degradation of bovine factor VIII, so that the exact role of carbohydrate groups in the aggregation process remains to be established.
mesh_terms: D000818:Animals; D001081:Apyrase / Q000494:pharmacology; D001241:Aspirin / Q000494:pharmacology; D012103:Batroxobin / Q000494:pharmacology; D001777:Blood Coagulation / Q000187:drug effects; D001792:Blood Platelets / Q000378:metabolism; D002417:Cattle; D005169:Factor VIII / Q000378:metabolism*; D006801:Humans; D007213:Indomethacin / Q000494:pharmacology; D010084:Oxidation-Reduction; D010974:Platelet Aggregation; D012701:Serotonin / Q000378:metabolism
chemical_list: D012701:Serotonin; D005169:Factor VIII; D012103:Batroxobin; D001081:Apyrase; D001241:Aspirin; D007213:Indomethacin