Plasminogen activator activity of cultured endothelial cells derived from canine coronary vessel and human umbilical artery and vein

The present study was undertaken to determine which cells participate in plasminogen activator (PA) release from the vascular wall. Canine coronary vessel was confirmed to release PA when various agents were administered in perfusion experiments. Endothelial cells from the coronary vessel were then isolated and cultured for 2 days. PA activity was observed in lysates of the cultured cells, and the medium used for the cultivation was found to contain little PA activity. This suggests that the endothelial cells participate in PA release from the vascular wall. In addition, the PA synthesis was also studied in cultured endothelial cells from human umbilical artery and vein. Both contained little PA activity, indicating that vascular endothelial cells may vary in PA synthesis and release according to the vessel.