TY - JOUR AU - Clozel, M AU - Fischli, W AU - Guilly, C T1 - Specific binding of endothelin on human vascular smooth muscle cells in culture. PY - 1989/05/01/ AB - Endothelin is a newly discovered, potent vasoconstrictor peptide secreted by endothelial cells. The binding of endothelin was studied on cultured human vascular smooth muscle cells obtained from umbilical veins. A single specific binding site for 125I-endothelin was identified, with an apparent Kd of 126 pM and a maximal binding capacity of approximately 10,000 sites per smooth muscle cell. At room temperature the binding was saturable, reached equilibrium at 2 h (using 20 pM endothelin), and was slowly and only partially reversed by unlabeled endothelin. The calcium antagonists nifedipine, nicardipine, and diltiazem did not compete for the same binding site. Conditioned medium from cultured human umbilical vein endothelial cells inhibited the binding of 125I-endothelin dose dependently. This effect was antagonized by anti-endothelin antiserum. We conclude that human umbilical vein smooth muscle cells possess specific binding sites for endothelin, and that human endothelial cells secrete an endothelinlike material. Images JF - The Journal of Clinical Investigation JA - J Clin Invest SN - 0021-9738 DO - 10.1172/JCI114078 VL - 83 IS - 5 UR - https://doi.org/10.1172/JCI114078 SP - 1758 EP - 1761 PB - The American Society for Clinical Investigation ER -