Urinary Excretion of Nitrogen from [¹⁵N]valine, [¹⁵N]leucine and [¹⁵N]isoleucine in Malnourished and Recovered Children Available to Purchase

1. l-Valine, l-leucine and l-isoleucine containing ¹⁵N were prepared, purified, and fed to marasmic and recovered infants. The excretion of total ¹⁵N and [¹⁵N]urea in the urine was followed for 72 h.

2. ¹⁵N excreted from isoleucine was about 90%, from leucine 70%, and from valine 50% in the recovered child.

3. ¹⁵N excreted was lower for leucine and isoleucine in marasmus than in recovery. The clinical state made little difference to ¹⁵N excretion from valine.

5. The decrease in excretion was almost entirely due to lowered urea output.

6. The results are discussed in relation to branched-chain amino acid metabolism and dietary requirements for these acids.