626 VBICACID METAHOLISM A\D aOT'T 



1lie liuman organism cannot desti-ny allaiitoiii.^^'' On tlu' other hand, 

 it lias been found repeatedly that nneleie aeid or purines given by 

 mouth are by no moans (|uantitatively excreted in the urine, even 

 when uric acid, allantoin and purine bases are added together. Ap- 

 parently a considerable proportion of the purine nitrogen fed, about 

 half in most experiments, is excreted as urea.^*'= As allantoin seems 

 not to be at all disintegrated in the human body it would seem prob- 

 able that if purines are destroyed, as these experiments indicate, they 

 pass through some other route than allantoin, and possibly that part 

 of the purines which is destroyed does not pass through the stage of 

 uric acid. Experiments show that outside the body uric acid can be 

 destroyed by other routes than through allantoin; thus, it can be dis- 

 integrated into glycocoll, ammonia and CO2 ; or by another method of 

 destruction it yields first alloxan (C4H2N2O4), then parabanic acid 

 (CjHoNjO.t) which in turn yields oxalic acid and urea. There is no 

 evidence, however, that any of these alternative routes is ever fol- 

 lowed in the aiiimal body. It is possible that the failure to find all 

 the purines of the food as uric acid in the urine depends on their par- 

 tial destruction in the intestine by bacteria.""^ It is highly probable, 

 in view of all available evidence, that in man most of the purine ab- 

 sorbed from the food, and practically all the purine from cell metabo- ■ 

 lism, is converted into uric acid and excreted as such. 



THE OCCTJRRENCE OF URIC ACID IN THE BLOOD, TISSUES. AND URINE 



As can be seen from the foregoing discussion, the amount of uric 

 acid that appears in the urine depends upon a number of factors, 

 which may be enumerated as follows: (1) The amount of purine 

 bodies taken in the food, upon which, chiefly, depends the amount of 

 exogenous uric acid. (2) The amount of destruction of tissue nucleo- 

 proteins. (3) The amount of purine bases formed in the muscle 

 tissue. (4) The amount of conversion of purine bases into the uric 

 acid. (5) The amount of destruction of uric acid, if any, occurring 

 in the body. (6) Possibly upon the capacity of the tissues to syn- 

 thesize uric acid ; and in case such power to synthesize uric acid exists, 

 uDon the presence of the precursors of uric acid in the body. (7) 

 The retention of uric acid in the blood and tissues. fS'i The power 

 of the kidneys to excrete uric acid. 



If we also take into account the fact that the solubility of uric acid 

 in the urine depends chiefly upon the amount of neutral phosphates 

 present in the urine, and also upon the temperature, reaction, and 



14b See Ac-krovd. T.iodiciti. .Tour., 1011 (.T), 217, 400, 442. 



Hf" Soe Taylor. Jour, r.i.il. Clioni.. 101.3 (14), 410; Hivons and TTuiitor. ihld.. lOlf) 

 (2.3), 200. A1)ont nno-toTilli as miieli uri(" acid is ovcrclcd in tlic swoat as in tlio 

 urine, sweat containinfr 0.1 ni<j;. ptT c.c. Adlor, Dout. .Arch. klin. ^fcd., 1016 

 (110), .')4S. 



i4d See Riven. Arcli. fjes. Tliysiol.. 1014 (157), 5S2. 



