title: Prostacyclin stimulation of the activation of blood coagulation factor X by platelets.
abstract: When platelets were incubated with prostacyclin, prostaglandin E1, or prostaglandin D2 at concentrations insufficient to increase the level of adenosine 3',5'-monophosphate (cyclic AMP), coagulation factor X was activated by a platelet cysteine protease. Prostacyclin or prostaglandin E1 at higher concentrations increased the cyclic AMP level and inhibited the activation of factor X by platelets. Inhibition of platelet adenylate cyclase by 2',5'-dideoxyadenosine allowed the activation of the protease at higher concentrations of the autocoids. Prostaglandins A1, A2, B1, B2, E2, F2 alpha, 6-keto-prostaglandin F1 alpha, and thromboxane B2, which do not affect platelet cyclic AMP level, did not stimulate the protease.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000527:Alprostadil / Q000494:pharmacology; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D002417:Cattle; D000242:Cyclic AMP / Q000378:metabolism; D003839:Deoxyadenosines / Q000031:analogs & derivatives / Q000494:pharmacology; D016048:Dideoxyadenosine / Q000031:analogs & derivatives*; D011464:Epoprostenol / Q000494:pharmacology*; D005170:Factor X / Q000502:physiology*; D006801:Humans; D010447:Peptide Hydrolases / Q000378:metabolism; D015230:Prostaglandin D2; D011453:Prostaglandins / Q000494:pharmacology; D011457:Prostaglandins D / Q000494:pharmacology
chemical_list: D003839:Deoxyadenosines; D011453:Prostaglandins; D011457:Prostaglandins D; D016048:Dideoxyadenosine; D005170:Factor X; C021008:2',5'-dideoxyadenosine; D011464:Epoprostenol; D000242:Cyclic AMP; D010447:Peptide Hydrolases; D000262:Adenylyl Cyclases; D000527:Alprostadil; D015230:Prostaglandin D2