Effects of anoxia, pyruvate, and lactate on distribution of N-13 glutamate in myocardium
The primary purpose of this study was to determine the effect of anoxia on the fate of N-13 labeled glutamate (glu) in myocardial tissue. Boluses of N-13-glu were injected arterially into isolated, arterially perfused rabbit interventricular septa under control conditions, during anoxia, and during perfusion with 2 mM pyruvate or lactate. In one set of experiments, time-activity curves were generated after the boluses. In another set of experiments, --0.1g of tissue was cut from the septum at 6 minutes after each injection. These samples were analyzed by reverse-phase HPLC. Under control conditions, glu accounted for 58% of the total N-13 radioactivity present in the sample and aspartate (asp), alanine (ala) and glutamine (gln) accounting for 20%, 16%, and 4%, respectively. During anoxia, the dominant change was an increase in ala to 40% of the N-13 radioactivity with an accompanying decrease in glu to 35%. Pyruvate perfusion produced a decrease in glu and increase in ala similar to the changes induced by anoxia. The changes due to lactate were in the same direction but less profound. Analysis of the time-activity curves revealed 2 components. The fraction of N-13 in the residual fraction was not different during anoxia as compared to control conditions. The t 1/2 of this fraction, however, became much shorter. The authors conclude that anoxia induces an increase in ala secondary to increased pyruvate availability. This is reflected in the time-activity curves as a faster washout of N-13 from the septa.
- Research Organization:
- UCLA School of Medicine, Los Angeles, CA
- OSTI ID:
- 6477803
- Report Number(s):
- CONF-840619-
- Journal Information:
- J. Nucl. Med.; (United States), Journal Name: J. Nucl. Med.; (United States) Vol. 25:5; ISSN JNMEA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AMINO ACIDS
ANIMAL CELLS
ANIMALS
ANOXIA
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BODY
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
CARDIOVASCULAR SYSTEM
DISTRIBUTION
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENZYME ACTIVITY
GLUTAMIC ACID
HEART
ISOTOPE APPLICATIONS
ISOTOPES
KETO ACIDS
LABELLED COMPOUNDS
LABELLING
LACTATES
LIGHT NUCLEI
MAMMALS
METABOLISM
MINUTES LIVING RADIOISOTOPES
MUSCLES
MYOCARDIUM
NITROGEN 13
NITROGEN ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PYRUVIC ACID
RABBITS
RADIOISOTOPES
RADIOPHARMACEUTICALS
TISSUE DISTRIBUTION
TRACER TECHNIQUES
UPTAKE
VERTEBRATES