BODY FLUIDS AND EFFECT OF HEREDITARY DISORDERS 201 
between men and women, #!, Several groups of workers have maintained that certain 
differences do exist but on the whole the variations are so subtle as to be insignificant. 
It is interesting, however, to note that there is an increase in the excretion of histidine 
during pregnancy®®: 3°. 
It has been known for many years that infants excrete more a-amino nitrogen than 
adults relative to their body weights®4. Paper-chromatographic studies of the urine 
of the newborn has confirmed this observation and has shown that certain amino 
acids are excreted preferentially?’ #°, 36, The most striking feature of the urine amino 
acid pattern of the newborn is the increased excretion of proline and hydroxyproline 
which commences on the 5—6th day and persists for about 5~6 months, after which 
time they are rarely, if ever, observed on paper chromatograms of urine from healthy 
people. The other amino acids which are involved in the increased aminoaciduria of 
the newborn are f-aminoisobutyric acid, lysine and taurine. Ethanolamine 1s also 
excreted in increased amount*®. 
The amino acid excretion of other mammals. The excretion pattern of the amino acids 
which is relatively constant within species can vary quite markedly between species. 
Datra AND Harris?” made a study of a number of different vertebrate species with 
respect to their amino acid excretion and the results are reproduced in Table III. It 
is noticeable that the carnivores excrete large amounts of 1-methylhistidine which 
is almost certainly derived from the dietary muscle tissue which is an abundant source 
of this amino acid. The domestic cat, and to a lesser extent the ocelot, is unique in 
excreting the amino acid felinine®* (S-hydroxyisopentanylcysteine, previously known 
as cat-spot). The Kenya genet excretes large amounts of cystine but does not suffer 
from stone formation as does the human cystinuric patient when excreting similar 
TABLE III 
THE PRINCIPAL AMINO ACIDS DETECTED BY PAPER CHROMATOGRAPHY IN THE URINES 
OF A NUMBER OF ANIMALS??* 
Glutamine or 
glutamic acid 
Methyl- 
Glycine Alanine Sais 
5 histidine 
Taurine “Cat-spot” Cystine 
Domestic cat on os = = SiG ele nee = ee yal ae 
Lion +- 4. ae ts Le 
Tiger + 
Ocelot + + ain _ ree = n 
Puma + ie = state + = tei) 
Genet ae a! — atts cae 
Binturong — — ie Tin = 
Dog = =|- - 45255 — 
Rabbit ae + ii = = = 
Rat Ab Ie areal = rans 
Mouse = _ = See ee = 
Guinea-pig + EE a = - 
Horse ab | fi a = 
Cow ae = = = 

* Reproduced by permission of the Physiological Society, London. 
References p. 217/219 
