Utilization for protein synthesis in individual rat organs of extracellular 2-ketoisocaproate relative to utilization of extracellular leucine

Journal Article · Sat Jul 01 04:00:00 EDT 1989 · Metab., Clin. Exp.; (United States)

DOI:https://doi.org/10.1016/0026-0495(89)90096-6· OSTI ID:5821606

Shiota, T; Yagi, M; Walser, M

Rats were given constant intravenous infusions of (/sup 3/H)-leucine plus (1-/sup 14/C)-2-ketoisocaproate (KIC). Specific activities of plasma leucine and plasma KIC reached plateaus by two to three hours. /sup 3/H specific activity of KIC was 85% +/- 2% of that in leucine. /sup 14/C specific activity of leucine was 36% +/- 2% of that in KIC. The /sup 14/C//sup 3/H ratios in leucine and KIC were constant from the earliest sampling time (one hour) at 0.65 +/- 0.03 and 2.20 +/- 0.07, respectively. In various tissues, /sup 14/C//sup 3/H in free leucine and in tissue protein were approximately equal, but in most organs these ratios were significantly greater than the ratio /sup 14/C//sup 3/H in plasma leucine. From these data we estimate that the fraction of leucine incorporated into protein in individual organs derived from extracellular KIC rather than extracellular leucine varies from zero (in liver and bone marrow) to 35% to 45% (in brain and heart), and comprises 12% in the body as a whole.

• Research Organization: Johns Hopkins Univ. School of Medicine, Baltimore, MD (USA)
• OSTI ID: 5821606
• Journal Information: Metab., Clin. Exp.; (United States), Journal Name: Metab., Clin. Exp.; (United States) Vol. 38:7; ISSN METAA
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMALS
BIOCHEMICAL REACTION KINETICS
BIOSYNTHESIS
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
DISTRIBUTION
ISOTOPE APPLICATIONS
ISOTOPE RATIO
KETO ACIDS
KINETICS
LABELLED COMPOUNDS
LEUCINE
MAMMALS
METABOLISM
ORGANIC ACIDS
ORGANIC COMPOUNDS
PROTEINS
RATS
REACTION KINETICS
RODENTS
SYNTHESIS
TISSUE DISTRIBUTION
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES