P. SOUPART 
1S) 
iS) 
CO 
amino nitrogen (free and combined, irrespective of the alpha or other position of the 
amino group). SouPpART”® has found that values for the total amino acid excretion, 
calculated from the column data in his group of 15 normal adults, ranged from 
0.48 to 1.11 g/24h in females and from 0.35 to 1.18 g/24h in males, the average 
figures being 0.73 and 0.80, respectively. The average figure found by STEIN? for 
men is 1.1 g/24h. When amino acid excretion is calculated from SoupaRtT’s data2° 
in terms of a-amino nitrogen, it appears that values range from 59 to 132 mg/24h 
in females and from 41 to 133 mg/24 hin males. The average figures are 87 and 91 mg 
respectively of a-amino nitrogen. These results are in very good agreement with the 
value of 1% of total nitrogen usually reported in the literature. 
3.000 > 85% of totalexcretion ¢—— | —y» < 15% of total excretion 
1.000 
500 

Riera 
TSW E it Se te 
eo oe 2 SS a 
Gly 
Tau 
His 
Met 
a AmAd 
Arg 
Orn 
1Me His 
Fig. 2. Aminoaciduria in normal healthy adults of both sexes. Open circles show normal variation 
range of individual daily outputs. Filled circles indicate average outputs. For glutamine, only 
approximate average value is given (see p. 222). 
Factors affecting free amino acid excretion in normal healthy adults. There is rather 
little information to be found on this point. As a general remark, it seems that free 
amino acid excretion varies within a narrow range in a given individual if followed 
in the course of time. There are of course some exceptions to this rule, namely 
1-methylhistidine, the excretion of which is correlated to meat consumption 
of the individual*?. Moreover taurine and f-aminoisobutyric acid excretion are 
increased when fasting for a sufficient duration is prescribed to a normal individual. 
On the other hand, there are rather large differences in free amino acid excretion 
when different individuals are compared. Among other factors which may affect 
free amino acid excretion in normal healthy adults the following may be listed: 
I) Menstrual cycle in females seems to influence the excretion of some of the free 
amino acids. This is particularly the case with histidine excretion. SouPART® 
has described the evolution of histidine output in the course of normal menstrual 
References p. 261/262 
