Effects of valine on 15N incorporation into serum and tissue protein and non-protein fractions following 15N-L-leucine administration to normal and liver-injured rats.
Effect of proportion of three branched-chain amino acids (leucine, valine, and isoleucine:BCAA) for nitrogen utilization was studied in vivo by an intragastric administration of 15N-L-leucine to control rats and liver-injured rats treated with carbon tetrachloride (CCl4-rats). Following the administration of isonitrogenous dose of three amino acid solutions [Standard (15N-L-leucine, L-valine, L-isoleucine, and L-alanine; 11, 8, 6, 18 mg/ml), Low-Val (11, 2, 6, 23 mg/ml), and High-Val (11, 32, 6, 0 mg/ml)], 15N enrichments in serum albumin, liver, skeletal muscle, and brain proteins and non-protein fractions, and urea nitrogen were compared by using 15N-analyzer. In CCl4-rats, the 15N enrichment in liver protein fraction was significantly lower in the High-Val group than in the Low-Val group. However, the difference of 15N enrichment in serum albumin between Low-Val and High-Val groups in CCl4-rats was unclear. The 15N enrichments in non-protein fractions of the brains in CCl4-rats were about twofold those in the skeletal muscles and the highest 15N enrichment was recognized in the Low-Val group. In the non-protein fraction of skeletal muscle in CCl4-rats, significantly low 15N enrichment was shown in the High-Val group compared with the Low-Val group. The 15N enrichment in urinary urea was significantly higher in the High-Val group than in the Low-Val group in CCl4-rats. In the Standard group of control rats, 15N enrichments in serum albumin and protein fraction of skeletal muscle were higher than in other groups. In non-protein fractions of control rats, the lowest 15N enrichment in liver and the highest 15N enrichment in skeletal muscle were recognized in the Standard group. These results suggest that a large amount of valine supplement among BCAA is less useful for leucine utilization in liver-injured rats than in normal rats.
Okita
M
M
Department of Food and Nutrition, Okayama Prefectural Junior College, Japan.
Watanabe
A
A
Tsuji
T
T
D000596:Amino Acids / Q000097:blood; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002251:Carbon Tetrachloride; D056486:Chemical and Drug Induced Liver Injury; D005260:Female; D007930:Leucine / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008107:Liver Diseases / Q000378:metabolism*; D009124:Muscle Proteins / Q000096:biosynthesis; D009132:Muscles / Q000187:drug effects / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes; D014176:Protein Biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D012709:Serum Albumin / Q000096:biosynthesis; D014508:Urea / Q000097:blood / Q000652:urine; D014633:Valine / Q000008:administration & dosage / Q000494:pharmacology*
D000596:Amino Acids; D009124:Muscle Proteins; D009587:Nitrogen Isotopes; D012709:Serum Albumin; D014508:Urea; D002251:Carbon Tetrachloride; D007930:Leucine; D014633:Valine; D009584:Nitrogen