Amino Aciduria in Normal Subjects

In children above 2 years of age, adolescents, and adults, the situation is much the same. An over-all indication of the situation in normals has already been given in Section 1.3. 

Soupart s data for histidine excretion are lower than those of Stein and of Evered because they do not include 3-methylhistidine. The data of Stein and Evered include 3-methylhistidine because their figures were obtained with Moore and Stein s 1951 method and not their 1954 method which was used by Soupart (S24). 

Normal urine contains only traces of y-aminobutyric acid and of tryptophan (only a few milligrams in 24 hours). We have already referred to the fact that tryptophan is an amino acid poorly recovered by Moore and Stein s 1954 technique. 

Comparison with values from the literature obtained by microbiological methods has been discussed by Stein (S32). The main objection to microbiological methods lies in the fact that amino acid derivatives or combined amino acids may be as readily available to the microorganisms used in these methods as are the parent amino acids from which they 

The data are grouped in Table 1 as well as in Fig. 1 drawn from Soupart s publication (S24 diets not controlled). 

---