Metabolic fate of radiolabeled palmitate in ischemic canine myocardium: implications for positron emission tomography

Journal Article · Sat Aug 01 04:00:00 EDT 1987 · J. Nucl. Med.; (United States)

OSTI ID:6021964

Rosamond, T L; Abendschein, D R; Sobel, B E; Bergmann, S R; Fox, K A

Interpretation of dynamic and integrated myocardial tomograms requires elucidation of the biochemical fate of the tracer and characterization of its tissue distribution and rate of efflux. The fate of (1-/sup 11/C) and (1-/sup 14/C)palmitate was studied in 13 open-chest dogs during control or ischemic extracorporeal perfusion of the left circumflex coronary artery. Residue detection of myocardial radioactivity, and radio-biochemical analyses of sequential transmural biopsies and arterial and coronary venous effluent were performed for 30 min after intracoronary bolus administration of tracer. In control hearts, 10.3% of initially extracted tracer was retained in tissue (2.9% in triglyceride, 3.5% in phospholipid, and 3.9% in other lipid and aqueous fractions), 73.7% was oxidized, and 16.1% back-diffused unaltered. With ischemia (pump flow 10% of normal), 28.1% was retained (18% in triglyceride, 6.0% in phospholipid, and 4.1% in other lipid and aqueous fractions), 27.2% was oxidized, and 44.4% back diffused (p less than 0.05 compared to control). Throughout the 30-min study interval, triglyceride, diglyceride, and nonesterified fatty acid comprised a significantly greater fraction of initially extracted radioactivity in ischemic than in control hearts. Thus, during ischemia externally detected clearance rates cannot be used as a direct measure of fatty acid metabolism because of marked influences on efflux of nonmetabolized radiolabeled palmitate and the distribution of tracer retained in tissue. Quantitative measurements of specific metabolic processes by tomography will require development and validation of tracers confined to individual metabolic pathways or pools.

• Research Organization: Washington Univ. School of Medicine, St. Louis, MO
• OSTI ID: 6021964
• Journal Information: J. Nucl. Med.; (United States), Journal Name: J. Nucl. Med.; (United States) Vol. 28:8; ISSN JNMEA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOLOGICAL PATHWAYS
BODY
CARBON 11
CARBON 14 COMPOUNDS
CARBON ISOTOPES
CARBOXYLIC ACIDS
CARDIOVASCULAR DISEASES
CARDIOVASCULAR SYSTEM
CLEARANCE
COMPUTERIZED TOMOGRAPHY
DIAGNOSIS
DIAGNOSTIC TECHNIQUES
DISEASES
DISTRIBUTION
DOGS
EMISSION COMPUTED TOMOGRAPHY
EVEN-ODD NUCLEI
HEART
HEXADECANOIC ACID
ISCHEMIA
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
MAMMALS
METABOLISM
MINUTES LIVING RADIOISOTOPES
MONOCARBOXYLIC ACIDS
MUSCLES
MYOCARDIUM
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
POSITRON COMPUTED TOMOGRAPHY
RADIOISOTOPES
TISSUE DISTRIBUTION
TOMOGRAPHY
VASCULAR DISEASES
VERTEBRATES