Angiotensin Converting Enzyme: Induction in Rabbit Alveolar Macrophages and Human Monocytes in Culture

Abstract

The biochemical complexity of mononuclear phagocytes and its regulation by various chemical signals, as well as the rich molecular regulatory interchange among these and other cell types, has become increasingly recognized in recent years (20). Angiotensin converting enzyme (ACE) (E.C. 3.4.15.1, peptidyl dipeptidase) is a glycoprotein of about 150,000 daltons which catalyzes the cleavage of the carboxy-terminal dipeptide of the decapeptide angiotensin I to form the biological potent pressor octapeptide, angiotensin-II, as well as a similar cleavage which inactivates bradykinin (19). ACE has been shown in the rabbit to be localized predominantly at the lumenal surface of endothelial cells (10), and is strkingly increased in the pathological tissues and sera of patients with sarcoidosis (8,14–16) and Gaucher’s disease (9,12,18), which are associated with proliferation of mononuclear phagocytes. This observation suggested that ACE may be abundant in sarcoidosis epithelioid cells and Gaucher cells as the cause of the ACE elevation in these conditions. This hypothesis (11, 16) has been born out by our recent localization by immunofluorescence of abundant ACE in these cells but not in other granulo-matous controls using an anti-human lung ACE antibody prepared in rabbits with the aid of purified human lung ACE (2,13).