Changes in brain and lung angiotensin converting enzyme activity in various shocks.

The brain and lung angiotensin converting enzyme (ACE) activities of the rats subjected to haemorrhagic, hypovolemic or endotoxic shock and of the mice immunized and then intravenously challenged with bovine serum albumin were determined by means of a spectrophotometric method. The lung ACE activities of all the shock groups were found significantly higher than those of their Control groups whereas only the brain ACE activities of the rats in endotoxic shock and the mice in anaphylactic shock showed a significant increase compared to their own control values. The results were interpreted as supporting evidence for the idea that peripheral and central renin-angiotensin systems may play a deleterious role in shock.