DIGESTION OF ENDOTHELIN-1 ON CULTURED VASCULAR SMOOTH-MUSCLE CELLS

The degradation of I-125-endothelin-1 (I-125-ET-1) was examined on cul tured porcine aortic endothelial cell (EC) and rat vascular smooth mus cle 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 eve n in plasma. This activity was inhibited with some of the noble inhibi tors which were known as enkephalinase inhibitors. These results sugge st that endothelin degradation enzyme on SMC is related to enkephalina se and that this enzyme plays a significant role in the degradation of ET-1 in vivo.