iS) 
40 P. SOUPART 
this figure, the amounts of amino acid filtered are expressed relatively to that of 
aspartic acid, assuming once again that individual amino acid concentrations are 
the same in the glomerular filtrate and in plasma. 
For alanine, which is the most abundantly filtered amino acid, 99.54% is re- 
absorbed in the average, and this percentage varies little among the group of indi- 
viduals investigated. At the opposite, aspartic acid, which is scarcely present in 
plasma, and thus filtered in rather small amount, is less effectively reabsorbed. In the 


Relative filtered loads (mean values) Percentage of reabsorption 
wo wo wo o wo wo wo © wo 25 
° rr) 3S Ss 3 3S Ss 3 &S o = i) w S a a N oo 6-8 
t LL 4 4 4 + 4 4 4 4 4 = 4 4 1 1 =: 4 4 
HIS pa =O oer | 


ASP | t — 



ILEU ———— 





VAL ro 
ORN " 
LYS “ 
PRO 4 
= aa —r T o T = T T T T T T Y am Jz TE Le ng T ps 
— a ow a @ ao wo wo wo wo wo wo wo wo wo wo e 
o So 3 r=) o o o = @ wo °o = nN wo rr a an x o wo so 
Fig. 7. Estimated efficiency of free amino acid reabsorption by the kidney, as compared with 
relative filtered loads. 
average, the less well-reabsorbed amino acids are histidine, taurine, aspartic acid 
and methionine, although some individuals distinguish themselves by fairly good 
reabsorption of these amino acids as shown by Table VI. Reabsorption of a few of 
the amino acids present in plasma has still not been correctly evaluated, in most 
cases owing to technical reasons which have been discussed previously. I- and 
3-methylhistidine, BAIBA, and f-alanine are generally considered as not being 
reabsorbed at all, since they are excreted in non-negligible amount, although they 
are only present in plasma as very faint traces when detectable. Proline, on the other 
hand, one of the most abundant amino acids in the plasma, is never found in normal 
urine. It is generally assumed that its reabsorption is complete. With this particular 
References p. 261/262 
