Bovine endothelial cells in culture produce thromboxane as well as prostacyclin

Abstract

Bovine aortic endothelial and smooth muscle cells in culture were incubated with arachidonic acid or prostaglandin H2. The amount of prostacyclin and thromboxane A2 synthesized was then determined by specific radioimmunoassay for 6-keto-prostaglandin F(1α) and thromboxane B2. Although smooth muscle cells produced only 6-ketoprostaglandin F(1α), endothelial cells produced 6-keto-prostaglandin F(1α) and thromboxane B2 in a ratio of 5:1 to 10:1. The same ratio of these metabolites of arachidonic acid was also found when prostaglandin production from endogenous arachidonic acid was stimulated in endothelial cells by the ionophore A23187. Cyclooxygenase inhibitors inhibited the production of both metabolites equally, whereas thromboxane synthetase inhibitors selectively inhibited the production of thromboxane B2. Cells in cultures were also incubated with [1-14C]arachidonic acid and the extracted products were identified by two-dimensional thin-layer chromatography. 6-Keto-prostaglandin F(1α) was the only metabolite produced by smooth muscle cells, but endothelial cells synthesized 6-keto-prostaglandin F(1α), thromboxane B2, prostaglandin E2, and prostaglandin F(2α).