Angiotensin II does not elicit any specific prostaglandin secretion in piglet cultured endothelial cells

PGE2 and PGF2 alpha were measured in culture media from piglet aortic endothelial cells by radioimmunological analysis. Prostacyclin secretion was evaluated by radioimmunological analysis of its stable metabolite, 6-keto-PGF1 alpha after reverse-phase high pressure liquid chromatography separation. No stimulation of either prostaglandin was detectable in culture media after treatment with angiotensin II (10(-9) to 10(-6) M) for 15 to 120 min at 37 degrees C. Under the same conditions angiotensin II (10(-7) M) elicited a 2 to 3 fold increase in PGE2 and PGF2 alpha secretion when incubated with cultured piglet aortic smooth muscle cells. In addition, we failed to detect specific angiotensin receptors at the surface of intact cultured endothelial cells. Since there was a very rapid increase in prostaglandin secretion after washing or medium changes we suggested that the effects of Angiotensin II on prostacyclin production, demonstrated in perfused organs, could be due to the mechanical stimulation elicited by the contraction of the underlying smooth muscle cells.