BODY FLUIDS AND EFFECT OF HEREDITARY DISORDERS 199 

TAU 
ALA SER 
CLU-NH, 
es 
Fig. 2. A paper chromatogram of normal human urine (sample taken contained 250 ug of total 
nitrogen). 
The urine amino acid excretion of the healthy human adult conforms to a fairly 
standard pattern which is only changed by disease or by a gross alteration in dietary 
intake. A paper chromatogram of a normal urine (the amount used contained 250 wg 
of total N) after treatment with ninhydrin to show up the main amino acids, is illus- 
trated in Fig. 2. Note the marked difference from the plasma pattern due to the inter- 
vention of the kidney. It will be seen that glycine is the most abundant amino acid 
excreted followed by histidine, taurine, glutamine, alanine and serine. This general 
pattern does not alter greatly from individual to individual and such changes that are 
usually observed are quite subtle. Further, the amino acid excretion pattern of the 
individual, after childhood, and providing he remains healthy, is constant over many 
years. However, one occasionally finds a variant from this pattern in a healthy person 
and an instance of this is seen in those people who excrete excessive amounts of /- 
aminoisobutyric acid!’ 14. A number of recent quantitative analyses of the amino 
acid content of normal human urine carried out by several investigators are set out 
in Table II. Reference to this list shows that glycine, taurine, t-methylhistidine and 
histidine are the only amino acids excreted in amounts exceeding 100 mg/day. All 
of the remaining protein-derived amino acids are found in the urine and are excreted 
References p. 217/219 
