bo 
30 P. SOUPART 
TABLE II 
DAILY URINARY OUTPUT OF 26 FREE AMINO ACIDS IN 15 NORMAL CHILDREN 
Seven girls and eight boys, white and black; age range 9 months—2 years. Values are 
expressed in y«wmoles/24 h (Dr. H. Vis!@). 

A. roamino acids (87% of total) 

Range Average 
Glycine I43— 561 370 
Histidine 99-— 533 300 
Glutamine* > 12—> 393 >170 
Alanine 64— 164 107 
Serine 65— 120 95 
Lysine hO—e Bl 70 
t-Methylhistidine O— 250 52 
Taurine 18— 112 52 
Threonine 26-74 48 
fp-aminoisobutyric acid o- 93 40 
Total > 1310 wmoles 

B. 9g amino acids (up to approx. 12% of total) 
Phenylalaline, 3-methylhistidine, tyrosine, ornithine, leucine, 
isoleucine, methionine sulfoxides, cystine 1/,, aspartic acid. 
Average output from 30-10 moles: 9 x 20 = 180 wmoles 

C. 8 amino acids (less than 1% of total) 
Arginine, valine, methionine, a-aminobutyric acid, y-amino- 
butyric acid, f-alanine, a-aminoadipic acid, proline. 
Average output 3 «moles: 3} <5 3 24 wmoles 
Grand total Approx. 1514 “moles 

* See footnote * in Table I. 
the free amino acid excretion pattern seems to be different from that found in adults. 
Table II gives free amino acid excretion data, in the same manner as those given 
for adults in Table I. These data are borrowed from a study done in the department 
pyar ELVis'= 
Although the absolute amounts of free amino acids excreted by this group of 
normal children (eight boys and seven girls, ages ranging from 9 months to 2 years) 
are very different in size from those found in adults, a convenient way of comparison 
is to express individual free amino acid average excretions in both cases in percent 
of the total average molar amount excreted in 24h. Such a comparison is shown 
in Fig. 3, for two groups of adults and children of comparable size and sex partition 
(data of Table I and Table IT). To be noticed is that the average excretion of histidine, 
glutamine, alanine, lysine and ornithine, are higher in children of this age group 
than they are in adults. On the other hand, the reverse situation is apparent with 
regard to taurine, I- and 3-methylhistidine, valine, f-alanine and a-aminoadipic 
acid. These observations are of special interest in light of our present knowl- 
edge of metabolism of some of the involved amino acids, namely taurine, 3-methyl- 
histidine and lysine. In the case of taurine, which is one of the end-products of 
sulfur amino acid metabolism, a rather low excretion is not surprising as sulfur 
retention is an essential requisite of growth. As regard to 3-methylhistidine, there 
References p. 261/262 
