Tissue specificity of endothelin binding sites

Journal Article · Sat Sep 01 04:00:00 EDT 1990 · Journal of Cardiovascular Pharmacology; (USA)

DOI:https://doi.org/10.1097/00005344-199009000-00004· OSTI ID:6073443

Bolger, G T; Liard, F; Krogsrud, R; Thibeault, D; Jaramillo, J ^[1]

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1. BioMega, Inc., Laval, Quebec (Canada)

A measurement was made of the binding of 125I-labeled endothelin (125I-ET) to crude membrane fractions prepared from rat aorta, atrium, ventricle, portal vein, trachea, lung parenchyma, vas deferens, ileum, bladder, and guinea-pig taenia coli and lung parenchyma. Scatchard analysis of 125I-ET binding in all tissues indicated binding to a single class of saturable sites. The affinity and density of 125I-ET binding sites varied between tissues. The Kd of 125I-ET binding was approximately 0.5 nM for rat aorta, trachea, lung parenchyma, ventricle, bladder, and vas deferens, and guinea-pig taenia coli and lung parenchyma, 1.8 nM for rat portal vein and atrium, and 3.3 nM for ileum. The Bmax of 125I-ET binding had the following rank order of density in rat tissues: trachea greater than lung parenchyma = vas deferens much greater than aorta = portal vein = atrium greater than bladder greater than ventricle = ileum. The properties of 125I-ET endothelin binding were characterized in rat ventricular membranes. 125I-ET binding was time dependent, reaching a maximum within 45-60 min at 25 degrees C. The calculated microassociation constant was 9.67 x 10(5) s-1 M-1. Only 15-20% of 125I-ET dissociated from its binding site even when dissociation was studied as long as 3 h. Preincubation of ventricular membranes with ET prevented binding of 125I-ET. 125I-ET binding was destroyed by boiling of ventricular membranes and was temperature, pH, and cation (Ca2+, Mg2+, and Na+) dependent.

• OSTI ID: 6073443
• Journal Information: Journal of Cardiovascular Pharmacology; (USA), Journal Name: Journal of Cardiovascular Pharmacology; (USA) Vol. 16:3; ISSN 0160-2446; ISSN JCPCD
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
DAYS LIVING RADIOISOTOPES
DISTRIBUTION
ELECTRON CAPTURE RADIOISOTOPES
GUINEA PIGS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PEPTIDES
PROTEINS
RADIOISOTOPES
RATS
REACTION KINETICS
RECEPTORS
RODENTS
TIME DEPENDENCE
TISSUE DISTRIBUTION
VERTEBRATES