278 K. SCHREIER 
C. LIQUOR CEREBROSPINALIS 
Of all the field of amino acid metabolism found in the literature the most contro- 
versial data concern liquor cerebrospinalis?®°-273_ This arises from the fact that the 
amino acid content is much lower than that of the plasma and therefore in uncon- 
centrated liquor the amino acid levels may be below the sensitivity of the methods 
employed. 
I doubt that the immense differences in values for single amino acids reported by 
different authors? are really due to biological variations. It is much more probable 
that they are caused by losses during the desalting procedure and other methodolog- 
ical inadequacies. It has been claimed that differences exist between the spinal 
liquor and that of the brain ventricles?“4. The data available in the literature are 
compiled in Table V. It was to be expected that all amino acids found in the other 
body fluids also would be detected in the liquor. KNAUFF ef al.?74 have found re- 
gularly 25 ninhydrin-positive substances of which 21 were amino acids. The great 
differences from the blood values demonstrate that the brain has its own way 
of handling amino acids. Since the reported values are so variable, no character- 
istic pattern of amino acid in the liquor for age groups or for any disease can be 
defined. Only in phenylketonuria is the phenylalanine level increased. Liver coma 
and presumably uremia change the amino acid content of the liquor in a non-specific 
way. It must be expected that increased permeability of the blood-brain barrier will 
increase the amino acids in the liquor on account of the high amino acid gradient 
between blood and liquor. 
D. ASCITES AND OTHER EXUDATES AND TRANSUDATES 
I was able to find two publications on amino acid content of trans- and exudates of 
the pleura and abdominal cavity?” 278. The amino acid levels in both types of effusion 
were of the same magnitude as in the blood plasma. It seems likely that the amino 
acids permeate passively from the blood into the exudates. 
E. PERSPIRATION (SWEAT) 
Amino acids also have been found regularly in sweat?®8,?77, To my knowledge quantita 
tive values have not yet been published. Arginine, citrulline and some unidentified 
spots in the position of tyrosine have always been found in the paper chromatogram 
of sweat. 
F. FECES 
Feces of infants fed human milk contain a greater amount of amino acids than those 
fed on cow milk formulas27°-271, This, of course, is due to differences in the bacterial 
flora. Escherichia coli incorporates amino acids not only with greater activity than 
lactobacilli, but also deaminates them more vigorously. 
References p. 279/283 
