Thrombin stimulates the production of immunoreactive endothelin-1 in cultured human umbilical vein endothelial cells.

The present study was designed to examine the effect of thrombin on endothelin production by cultured human umbilical vein endothelial cells (HUVEC) by radioimmunoassay. Cultured HUVEC released immunoreactive endothelin-1 (ir-endothelin-1) into the medium in a time-dependent manner. This release was inhibited completely by 10 micrograms/mL cycloheximide and is, therefore, directly related to de novo protein synthesis. Further endothelin release was stimulated by the addition of thrombin to the culture medium. Thrombin-induced ir-endothelin-1 release also was inhibited completely by 10 micrograms/mL cycloheximide. These results suggest that HUVEC in culture produce ir-endothelin-1 slowly, but continuously, and that this production is stimulated by thrombin.