Induction of angiotensin I-converting enzyme by captopril in cultured human endothelial cells.

Captopril (2.0 microgram/ml) increased angiotensin-converting enzyme (ACE, kininase II) activity from 6- to 16-fold in culture medium of human endothelial cells from umbilical cord artery. Immunohistochemically detectable ACE was markedly increased in these cells when using rabbit antihuman lung ACE antiserum. This accords with either observations of increased ACE activity in serum and lungs from rats treated with captopril and shows induction of ACE biosynthesis in human vascular endothelial cells in culture. This observation offers a tool for studying the mechanism of ACE induction.