Localization of angiotensin converting enzyme in rat heart

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Circulation Research (An Official Journal of the American Heart Association); (USA)

DOI:https://doi.org/10.1161/01.RES.68.1.141· OSTI ID:6250463

Yamada, H; Fabris, B; Allen, A M; Jackson, B; Johnston, C I; Mendelsohn, A O ^[1]

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1. Univ. of Melbourne, Victoria (Australia)

Angiotensin converting enzyme (ACE) was localized in rat heart by quantitative in vitro autoradiography with 125I-351A as the radioligand. The binding association constant (KA) of the radioligand was measured in membrane-rich fractions of atrium, ventricle, and lung by a radioinhibitor binding assay. A single class of high-affinity binding sites was detected in each tissue, and a significant difference was found between KA values for atria and ventricles with a rank order of atria greater than lungs greater than ventricles. For autoradiography, coronal sections (10 micron) of the frozen heart were incubated with 125I-351A and exposed to x-ray film. The autoradiographs were quantitated by computerized image analysis. The highest density of ACE in the heart was found on valve leaflets (aortic, pulmonary, mitral, and tricuspid), which contrasted markedly with very low ACE labeling in the endocardium. The coronary arteries also showed dense labeling of ACE. The right atrium had a moderate density of ACE, which was higher than the left atrium and the ventricles. Both the endothelial and adventitial layers of the aorta and pulmonary artery displayed high densities of ACE, with very low density in the media. ACE was not detected in either the sinoatrial node or atrioventricular node. These results reveal a markedly nonuniform localization of ACE in the rat heart and suggest possible sites for local angiotensin II generation and bradykinin or other peptide metabolism.

• OSTI ID: 6250463
• Journal Information: Circulation Research (An Official Journal of the American Heart Association); (USA), Journal Name: Circulation Research (An Official Journal of the American Heart Association); (USA) Vol. 68:1; ISSN CIRUA; ISSN 0009-7330
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL TISSUES
ANIMALS
AORTA
ARTERIES
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL LOCALIZATION
BLOOD VESSELS
BODY
CARDIOVASCULAR SYSTEM
DAYS LIVING RADIOISOTOPES
DISTRIBUTION
ELECTRON CAPTURE RADIOISOTOPES
ENDOTHELIUM
ENZYME INHIBITORS
ENZYMES
HEART
HYDROLASES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
KINETICS
LIGANDS
MAMMALS
MEMBRANE PROTEINS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HYDROLASES
PROTEINS
RADIOISOTOPES
RATS
REACTION KINETICS
RECEPTORS
RODENTS
TISSUE DISTRIBUTION
TISSUES
VERTEBRATES