Characterization of beta-adrenoreceptors in vivo with iodine-131 pindolol and gamma scintigraphy

Journal Article · Thu May 01 00:00:00 EDT 1986 · J. Nucl. Med.; (United States)

OSTI ID:5207507

Hughes, B; Marshall, D R; Sobel, B E; Bergmann, S R

The aim of this study to was to assess the feasibility of using iodopindolol to delineate myocardial beta-adrenoreceptors in vivo. Preliminary biodistribution studies indicated that binding of /sup 131/I-d,I-pindolol in the heart was stereospecific, saturable, and displaceable by I-propranolol but not by phenoxybenzamine. However, considerable nonspecific binding was encountered. Subsequently, the stereoisomer, /sup 131/I-I-pindolol, was shown to be a high affinity beta-adrenoreceptor antagonist (Kd approximately 0.37 nM) as assessed by Scatchard analysis, and one exhibiting marked specific uptake in lung and heart in rabbits. In contrast, /sup 131/I-d-pindolol exhibited no specific binding in rabbit left ventricular membrane preparations nor specific organ uptake. Gamma camera scintigraphy with both isomers demonstrated that the I-isomer accumulated in lung and heart, and that its accumulation was blocked by I-propranolol. In contrast, d-isomer uptake was nonspecific and diffuse. The results indicate that it should be possible to externally visualize receptors by differentiating specific and nonspecific binding components of a ligand in vivo with the use of radiolabeled stereoisomers.

• Research Organization: Washington Univ. School of Medicine, St. Louis, MO
• OSTI ID: 5207507
• Journal Information: J. Nucl. Med.; (United States), Vol. 5
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ADRENALINE
RECEPTORS
MYOCARDIUM
SCINTISCANNING
CELL MEMBRANES
IODINE 131
RABBITS
RATS
TISSUE DISTRIBUTION
ADRENAL HORMONES
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARDIOTONICS
CARDIOVASCULAR AGENTS
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
COUNTING TECHNIQUES
DAYS LIVING RADIOISOTOPES
DIAGNOSTIC TECHNIQUES
DISTRIBUTION
DRUGS
HEART
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
MUSCLES
NEUROREGULATORS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RADIOISOTOPE SCANNING
RADIOISOTOPES
RODENTS
STEROID HORMONES
SYMPATHOMIMETICS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques