Higher excretion of urinary bound amino acids in infants: probably related to protein-anabolic effect of growth hormone.

Concentrations of bound amino acids in urine were found to be markedly higher in infants than in children over 4 years of age. And it was also found that bound amino acid levels in plasma were increased in infants and young children than in adults. Urinary excretion of bound amino acids was increased in hypopituitary dwarf after one day of intramuscular injection of human growth hormone. A possibility was advanced that an increased excretion of bound amino acids of the overflow type observed in infants was due to active protein biosynthesis stimulated by growth hormone of which plasma levels have been reported to be high in infancy.