Specific binding of leukotriene C4 to endothelial cell membranes

Vascular endothelium is a target for leukotriene C4 (LTC4) as demonstrated by previous in vivo and culture experiments. Binding assays were carried out at 0 degrees C on membrane fraction obtained from bovine aortic endothelial cells in culture. Specific binding sites (Kd = 49.9 +/- 6.3 nmol X 1(-1), N = 1.2 X 10(6) sites per cell) for LTC4 were demonstrated in this preparation. Competition studies showed that LTB4, LTD4 and LTE4 did not displace LTC4 from its binding sites. FPL 55712, a sulfidopeptide antagonist, was seen to be a weak competitor and reduced glutathione exhibited a significant affinity for the binding site. The possible receptor role of this site is discussed.