| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1990: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1989: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Utilization and metabolism of leucine and valine were studied comparatively by intragastric administration of ^<15>N-L-leucine (^<15>N-L-Leu) and ^<15>N-L-valine (^<15>N-L-Val) to control- and liver-injured rats treated with carbontetrachloride (CCl_4-rats). Following the administration of 250 mu mol/100g body weight ^<15>N-L-Leu or ^<15>N-L-Val, ^<15>N concentrations in serum albumin and liver, skeletal muscle and brain proteins and non-protein fractions and urine were analyzed using ^<15>N-analyzer. Free amino acid concentrations in plasm, skeletal muscle and brain were analyzed by HPLC. alpha-keto acids were analyzed using gaschromatography.
(1) In CCl_4-rats, plasma leucine concentration increased slowly and decreased rapidly following ^<15>N-L-Leu administration. However, Plasma valine concentration reached the extremely high level (2328<plus-minus>199 nmol/ml) and decreased very slowly following ^<15>N-L-Val administration. (2) In CCl_4-rats, ^<15>N concentrations in serum albumin
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, liver and skeletal muscle proteins were significantly higher in ^<15>N-Leu group than those in ^<15>N-Val group 5 h following ^<15>N-L-Leu and ^<15>N-L-Val administration. (3) Brain ^<15>N concentration in CCl_4-rats was higher than that in control rats in both protein and non-protein fractions 5 h following ^<15>N-L-Leu administration. In CCl_4-rats, significantly high ^<15>N concentration in brain non-protein fraction was recognized in ^<15>N-Leu group compared to ^<15>N-Val group 5 h following ^<15>N-L-Leu and ^<15>N-L-Val administration, and incorporation of ^<15>N into brain protein was also higher in ^<15>N-Leu group than that in ^<15>N-Val group 24 h following ^<15>N-L-Leu and ^<15>N-L-Val administration. (4) In CCl_4-rats, urinary ^<15>N excretion was larger than in control rats and urea-^<15>N excreted during 5 h follwing ^<15>N-L-Leu administration was twice of that in ^<15>N-Val group.
These results suggest the effective utilization of leucine for protein synthesis in the liver and muscle of liver-injured rats. In addition, rapid disappearance of leucine from plasma and large amount of ^<15>N excretion into urine following ^<15>N-L-Leu administration indicate that leucine can be oxidized and resultant non-protein nitrogen can be excreted into urine in a short time in liver-injured rats. Less
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