Valine entry into rat brain after diet-induced changes in plasma amino acids

Journal Article · Thu Jan 01 04:00:00 EST 1987 · Am. J. Physiol.; (United States)

OSTI ID:6218979

Tews, J K; Greenwood, J; Pratt, O E; Harper, A E

Passage of amino acids across the blood-brain barrier is assumed to be modified by amino acid composition of the blood. To gain a better understanding of the effects of protein intake on brain amino acid uptake, the authors examined associations among diet, plasma amino acid patterns, and the rate of entry of valine into the brain. Rats were fed diets containing 6, 18, or 50% casein before receiving one meal of a diet containing 0, 6, 18, or 50% casein. After 4-7 h, they were anesthetized and infused intravenously with (/sup 14/C)valine for 5 min before plasma and brain samples were taken for determination of radioactivity and content of individual amino acids. As protein content of the meal was increased from 0 to 50% casein, plasma and brain concentrations of valine and most other large neutral amino acid (LNAA) increased severalfold; also the ratio of (/sup 14/C)valine in brain to that in plasma decreased by >50%, and the rate of valine entry into the brain increased 3.5-fold. The increase in valine flux slowed as plasma levels of LNAA, competitors for valine transport, increased. The results were far more dependent on protein content of the final meal than on that of the adaptation diet; thus changes in protein intake, as reflected in altered plasma amino acid patterns, markedly altered valine entry into the brain.

• Research Organization: Univ. of Wisconsin, Madison
• OSTI ID: 6218979
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 252:1; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMALS
BLOOD CHEMISTRY
BLOOD-BRAIN BARRIER
BODY
BRAIN
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CENTRAL NERVOUS SYSTEM
DIET
INGESTION
INTAKE
LABELLED COMPOUNDS
MAMMALS
MEMBRANE TRANSPORT
NERVOUS SYSTEM
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PHYSIOLOGY
RATS
RODENTS
VALINE
VERTEBRATES