Digestion of endothelin-1 on cultured vascular smooth muscle cells

The degradation of 125I-endothelin-1 (125I-ET-1) was examined on cultured porcine aortic endothelial cell (EC) and rat vascular smooth muscle cell (SMC) by HPLC analysis. The degradation of ET-1 was observed on SMC and was slightly observed on EC. Membrane fractions of SMC had a strong potency for the degradation of ET-1 and retained activity even in plasma. This activity was inhibited with some of the noble inhibitors which were known as enkephalinase inhibitors. These results suggest that endothelin degradation enzyme on SMC is related to enkephalinase and that this enzyme plays a significant role in the degradation of ET-1 in vivo.