The purpose of this study was to determine tissue angiotensin I-converting enzyme (ACE) activity in ageing hamsters with and without cardiomyopathy, and the factors that regulate its activity in vitro. We found that ACE activity was significantly increased in the heart and significantly decreased in the lung of ageing hamsters with hereditary cardiomyopathy in comparison to age/genetically-matched controls (P < 0.05). Kidney and cheek pouch ACE activity was similar in both groups. Lisinopril inhibition curves of tissue ACE activity were similar in ageing hamsters with and without cardiomyopathy. In both groups, tissue ACE activity was dependent on chloride anion concentration in the assay buffer. Substituting citrate for chloride abrogated, in part, this response. We conclude that cardiomyopathy is associated with significant changes in cardiac and lung ACE activity in ageing hamsters in comparison to age/genetically-matched controls. However, regulation of tissue ACE activity in vitro is similar in both groups.
- Heart failure
- Proteinase inhibitors