Relationship between soluble intracellular endothelin-converting enzyme and endothelin-1 synthesis: Effect of inhibitors of the secretory pathway

The relationship between soluble and membrane-bound endothelin-converting; enzyme (ECE) activity with the level of endothelin-1 (ET-1) synthesis was i nvestigated in cultured endothelial cells. Escherichia coli lipopolysacchar ide (LPS) was used to stimulate ET-1 synthesis, and brefeldin A, monensin, colchicine or cytochalasin B, which disrupt peptide biosynthetic pathways i n a variety of ways, were tested for their ability to modify changes in ET- 1 synthesis and ECE levels. LPS increased ET-1 secretion by more than twofo ld. Levels of soluble ECE activity, but not those of membrane-bound ECE act ivity, correlated with ET-1 synthesis. These results suggest the soluble EC E activity is likely to play a role in ET-1 biosynthesis.