Nitrogen sparing by 2-ketoisocaproate in parenterally fed rats

Journal Article · Thu Nov 01 04:00:00 EST 1990 · American Journal of Physiology; (USA)

OSTI ID:6171716

Yagi, M; Matthews, D E; Walser, M ^[1]

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1. Johns Hopkins Univ. School of Medicine, Baltimore, MD (USA)

In rats receiving total parenteral nutrition with or without sodium 2-ketoisocaproate (KIC; 2.48 g.kg-1.day-1), L-(1-{sup 13}C)leucine and (1-{sup 14}C)KIC were constantly infused for 6 h. CO{sub 2} production, {sup 14}CO{sub 2} production, {sup 13}CO{sub 2} enrichment, urinary urea nitrogen (N) plus ammonia N and total urinary N were measured. Whole body protein synthesis (S) was calculated in non-KIC-infused rats and also in unfed rats infused with (1-{sup 14}C)leucine from fractional oxidation of labeled leucine (1-F), where F is fractional utilization for protein synthesis, and urea N plus ammonia N excretion (C) as S = C x F/(1-F). Addition of KIC caused a significant reduction in N excretion and a significant improvement in N balance. Fractional oxidation of labeled KIC increased, whereas fractional utilization of labeled KIC for protein synthesis decreased, but the extent of incorporation of infused KIC into newly synthesized protein (as leucine) amounted to at least 40% of the total rate of leucine incorporation into newly synthesized whole body protein. We conclude that addition of KIC spares N in parenterally fed rats and becomes a major source of leucine for protein synthesis.

• OSTI ID: 6171716
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 259:5 Pt 1; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMALS
BIOCHEMICAL REACTION KINETICS
BIOSYNTHESIS
CARBON 13
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON ISOTOPES
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
EVEN-ODD NUCLEI
FASTING
ISOTOPE APPLICATIONS
ISOTOPES
KETO ACIDS
KINETICS
LABELLED COMPOUNDS
LEUCINE
LIGHT NUCLEI
MAMMALS
NITROGEN
NONMETALS
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PROTEINS
RATS
REACTION KINETICS
REDOX REACTIONS
RODENTS
STABLE ISOTOPES
SYNTHESIS
TRACER TECHNIQUES
VERTEBRATES