Synthesis of Leukotrienes by Freshly Harvested Endothelial Cells

Endothelial cells produce endothelin, a powerful vasoconstrictor. We report the release of additional vasoconstrictor material in conditional filtrate from freshly harvested cells, which we identified as leukotrienes by radioimmunoassay (RIA) and by high pressure liquid chromotography (HPLC). The material was collected in cell free filtrates by superfusion of freshly harvested bovine endothelial cells attached to cytodex-3 microcarrier beads. Cells and beads form a dense network on filter paper permitting collection of cell free filtrate. The amount of leukotrienes in conditioned filtrate was 158 ± 21 picograms/million cells. The calcium ionophore A23187 stimulated the release of leukotrienes (392.0 ± 47.6). The peak of leukotriene production occurred within an hour after incubation of cells slowly declining thereafter. Conditioned filtrate to which indomethacian had been added caused coronary vasoconstriction in the perfused rat heart preparation, as did synthetic leukotrienes C+, D+ and E+. It was found by RIA and HPLC that some of the constrictor effect of conditioned filtrate derived from leukotrienes.