EICOSANOID PRODUCTION BY HUMAN AORTIC ENDOTHELIAL-CELLS IN RESPONSE TO ENDOTHELIN

Endothelial cells actively regulate their environment by secreting hum oral substances, including endothelin-1 and a variety of eicosanoids, that have local actions. To elucidate interactions among these local m ediators, we measured release of cyclooxygenase and lipoxygenase pathw ay products of arachidonate metabolism by human aortic endothelial cel ls after incubation with endothelin-1. Supernatants were collected, ex tracted, and fractionated using high-performance liquid chromatography . Radioimmunoassays for eicosanoids were performed on the appropriate fractions. After endothelin stimulation, production of the prostacycli n metabolite 6-ketoprostaglandin F-1 alpha (6-keto-PGF(1 alpha)), the thromboxane (Tx) metabolite TxB(2), and prostaglandin E(2) (PGE(2)) we re increased (307 +/- 48, 320 +/- 91, and 315 +/- 74% of control, P < 0.05). Leukotriene B-4 (LTB(4)) release was modestly increased (195 +/ - 19% of control, P < 0.05). The release of 5-hydroxyeicosatetraenoic acid (5-HETE) was increased (300 +/- 57% of control, P < 0.05); produc tion of 12-HETE and 15-HETE was unchanged. Production of eicosanoids p eaked between 30 and 120 min. Preincubation with pertussis toxin preve nted increased production of PGE(2), LTB(4), and 5-HETE after endothel in-1 stimulation; pretreatment with sphingosine had no effect. Interac tions between endothelin and eicosanoids may be important components o f the complex network that regulates vascular tone, coagulation, and i nflammation at the local level.