Synthesis of prostaglandin I2 (prostacyclin) by cultured human and bovine endothelial cells.

Abstract

Cultured endothelial cells derived from human umbilical veins or bovine aorta produce a potent inhibitor of platelet aggregation. The inhibitor is synthesized from sodium arachidonate or prostaglandin endoperoxides by a microsomal enzyme system. Tranylcypromine, a specific antagonist of prostacyclin synthetase, suppresses production of the inhibitor by endothelial cells. The inhibitor, which is ether extractable, was identified using a 2-step thin-layer radiochromatographic procedure and a synthetic prostaglandin[PG]I2 standard. Human and bovine endothelial cells convert sodium [3H]arachidonate to radiolabeled PGI2 and 6-keto-PGF1.alpha. and PGE2. Endothelial cells may be non-thrombogenic in vivo because they synthesize and release PGI2, a potent inhibitor of platelet aggregation.