Relation between plasma and tissue parameters of leucine metabolism in fed and starved rats

Journal Article · Sun Jun 01 04:00:00 EDT 1986 · Am. J. Physiol.; (United States)

OSTI ID:6897766

Vazquez, J A; Paul, H S; Adibi, S A

By use of a primed continuous infusion of (1-/sup 14/C)leucine, the authors investigated parameters of leucine metabolism in plasma, expired air, and tissues of fed and 48-h starved rats. The ratios of muscle to plasma specific activity of ..cap alpha..-ketoisocaproate (KIC) in fed and starved rats were not significantly different from 1. The ratio of muscle to plasma specific activity of leucine was also not significantly different from 1 in fed rats, but was significantly lower than 1 in starved rats. The rate of leucine oxidation was 28-34% higher when calculation was based on plasma KIC rather than leucine specific activity. However, starvation significantly increased the rate of leucine oxidation with either specific activity. The rates of leucine incorporation into whole-body protein, calculated as the difference between plasma leucine turnover and oxidation, were unaffected by starvation, but the incorporations into total protein measured directly were significantly decreased in liver and muscle. They conclude that a) leucine or KIC specific activity in muscle is better predicted by plasma KIC than leucine specific activity, and b) the difference between rates of plasma leucine turnover and oxidation does not appear to be a valid measurement of leucine incorporation into whole-body protein.

• Research Organization: Univ. of Pittsburgh, PA
• OSTI ID: 6897766
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 250:6; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL MATERIALS
BIOSYNTHESIS
BLOOD
BLOOD PLASMA
BODY FLUIDS
CARBON 14 COMPOUNDS
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
LABELLED COMPOUNDS
LEUCINE
MAMMALS
MATERIALS
NUTRITIONAL DEFICIENCY
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDATION
PROTEINS
RATS
RODENTS
SYNTHESIS
VERTEBRATES