Endothelin-induced prostacyclin production in rat aortic rings is mediated by protein kinase C.

G K Oriji, J E Tate, H R Keiser

Index: Prostaglandins Leukot. Essent. Fatty Acids 55(5) , 309-13, (1996)

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Abstract

Endothelin (ET) is a vasoconstrictor peptide released from endothelial cells that is known to cause prostaglandin release. The mechanism remains unclear. To determine whether the protein kinase C (PKC) signaling pathway is stimulated by endothelin, we pretreated rat aortic rings with either PKC activator or inhibitors and measured the release of prostacyclin (PGI2) by radioimmunoassay. ET (10(-9) M) produced a 10-fold increase in PGI2 release. Pretreatment with 10(-9) M of three different PKC inhibitors, 1-(5-isoquinolinesulfonyl)piperazine(CL), staurosporine, and 1-(5-isoquinolinesulfonyltmethyl)piperazine (H7), blocked ET-induced PGI2 release. ET-induced PGI2 release was also blocked by pretreatment with inhibitors of either phospholipase A2 7,7-dimethyleicosadienoic acid or trifluoromethyl ketone analogue) (10(-9) M) or cyclooxygenase (indomethacin) (10(-9) M). We conclude that ET activates PKC, which activates phospholipase A2, which liberates arachidonic acid, which increases PGI2 production and release.