Human platelet secreted proteins and prostacyclin production by bovine aortic endothelial cells.
The effects of specific human platelet-secreted proteins on prostacyclin (PGI2) production by primary cultures of bovine aortic endothelial cells have been studied. Cells were incubated with various concentrations of highly purified preparations of platelet factor 4 (PF4), low-affinity platelet factor 4 (LA-PF4), beta-thromboglobulin (beta TG), platelet basic protein (PBP), and partially purified platelet-derived growth factor (PDGF) in the presence or absence of arachidonic acid (AA). The amount of 6-Keto-PGF1 alpha, the stable degradation product of PGI2, was determined in the cell incubation medium by means of a specific radioimmunoassay. Short-term (15 min) incubation of cell monolayers with either LA-PF4 or beta TG slightly reduced 6-keto-PGF1 alpha production. The effect was not dose-related and could not be observed after prolonged (24 hr) incubation of the cells with the same proteins. It was not seen in the cell suspensions. Moreover, 6-keto-PGF1 alpha production stimulated by AA was not affected by incubation with either of the proteins. PF4 and PBP had no significant effect on 6-keto-PGF1 alpha production by endothelial cells. Human PDGF showed a slight tendency to stimulate 6-keto-PGF1 alpha release when cells were incubated for 24 hr with the protein; however, PDGF did not potentiate the stimulatory effect of AA on 6-keto-PGF1 alpha release by the cells. We suggest that platelet-derived proteins exert only a moderate and possibly nonspecific effect on PGI2 production by endothelial cells.
D015121:6-Ketoprostaglandin F1 alpha / Q000096:biosynthesis; D000818:Animals; D001011:Aorta; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology; D001792:Blood Platelets / Q000502:physiology*; D001798:Blood Proteins; D002417:Cattle; D002478:Cells, Cultured; D004727:Endothelium / Q000378:metabolism*; D011464:Epoprostenol / Q000096:biosynthesis*; D006133:Growth Substances / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology; D010978:Platelet Factor 4 / Q000494:pharmacology; D010982:Platelet-Derived Growth Factor; D011453:Prostaglandins / Q000096:biosynthesis*; D011460:Prostaglandins F / Q000096:biosynthesis; D001620:beta-Thromboglobulin
D001095:Arachidonic Acids; D001798:Blood Proteins; D006133:Growth Substances; D010455:Peptides; D010982:Platelet-Derived Growth Factor; D011453:Prostaglandins; D011460:Prostaglandins F; D001620:beta-Thromboglobulin; D016718:Arachidonic Acid; D010978:Platelet Factor 4; D015121:6-Ketoprostaglandin F1 alpha; D011464:Epoprostenol