K. Shibata et al., EFFECT OF ADDING BRANCHED-CHAIN AMINO-ACIDS TO A NICOTINIC ACID-FREE,LOW-PROTEIN DIET ON THE CONVERSION RATIO OF TRYPTOPHAN TO NICOTINAMIDE IN RATS, Bioscience, biotechnology, and biochemistry, 58(5), 1994, pp. 970-971
The effects of adding branched-chain amino acids to a nicotinic acid-f
ree, low-protein diet on the conversion of tryptophan to nicotinamide
were investigated in rats. The conversion ratio [urinary excretion of
nicotinamide and its metabolites (mu mol/day)x100/tryptophan intake du
ring urine collection (mu mol/day)] was significantly lower in the gro
ups fed with the 3% Leu-, Val-, or Ile-added diet than in the group fe
d with the control diet. Namely, the inhibition of this conversion was
observed not only by the addition of Leu, but also by the addition of
Val or Ile. The addition of Ile and/or Val to the Leu-added diet did
not antagonize the Leu effect.