Regulation of Prostacyclin Generation by Angiotensin Converting Enzyme Related Substances in Cultured Human Vascular Endothelial Cells

Abstract

The regulation of prostacyclin (PGI₂) generation by angiotensin I-converting enzyme (ACE) related substances was investigated using cultured human vascular endothelial cells. Angiotensin I (AI) or bradykinin (BK) increased PGI₂ generation and ACE activity, while the ACE inhibitor, captopril decreased both of them, and angiotensin II (AII) did not show any effect. The increasing rate of PGI₂ generation induced by AI or BK was not affected by the pretreatment with captopril. These results suggest that the accumulation of AI or BK via the inhibition of ACE by captopril did not cause the enhancement of PGI₂ generation. Rather, it was proposed that the enhanced PGI₂ generation by AI or BK might be regulated by ACE activation derived from these substances, as an autoregulation mechanism.

Key Words:

• prostacyclin
• angiotensin converting enzyme
• captopril