Enhanced angiotensin converting enzyme binding in arteries from spontaneously hypertensive rats.

Aim: To localize and measure angiotensin converting enzyme (ACE) in different vascular beds of genetically hypertensive rats.

Methods: Quantitative autoradiography using the angiotensin converting enzyme (E.C. 3.4.15.1) inhibitor [125I]351A.

Results: [125I]351A binding was significantly increased in the ascending aorta (both adventitia and intima), descending (abdominal) aorta, carotid artery and coronary arteries of adult, 12-week-old spontaneously hypertensive rats (SHR) compared with Wistar-Kyoto (WKY) rats. Increased [125I]351A binding was also present in the descending aorta of 1-week-old SHR compared with age-matched WKY rats, and both groups of young rats had much higher binding than adult rats. No difference in [125I]351A binding was found in the caudal (tail) artery of adult SHR compared with WKY rats. In both the atria and the ventricles of adult SHR, [125I]351A binding was very significantly reduced.

Conclusions: Our results indicate that higher ACE concentrations occur in some arteries of genetically hypertensive rats, and support the hypothesis that local arterial concentrations of ACE affect the development and maintenance of genetic hypertension.