Section V, 1919 [7] Trans. R.S.C. 



Comparative Studies of Purine Metabolism in Various Representative 



Mammals 



Bv Andrew Hunter, M.A., B.Sc, M.B., F.R.S.C., and 

 F. W. Ward, B.A.Sc. 



(Read May Meeting, 1919.) 



The urinary constituents representative in the mammaha of 

 successive steps in purine metaboHsm are purine bases (chiefly xanthine 

 and hypoxanthine), uric acid, and allantoin. While none of these 

 appears ever to be entirely absent, the proportions in which they are 

 excreted vary greatly from species to species. In human urine, for 

 instance, allantoin has been detected in such insignificant traces, 

 that for all practical purposes the catabolism of purines in man may 

 be said to terminate at the stage of uric acid. The other extreme is 

 represented by such an animal as the dog, in which 97 per cent of 

 the urinary nitrogen derived from purines may be present as allantoin, 

 and uric acid assumes a relatively unimportant position. By the 

 systematic comparison, from this point of view, of many different animals 

 several other types of purine metabolism have been distinguished. It 

 becomes of interest therefore to ascertain to what extent these types 

 are definitely characteristic of zoological species or groups, and 

 whether between the extremes represented there is any such gradation, 

 as would correspond to the probable course of evolutionary develop- 

 ment. 



The list of species already studied, either by ourselves or others, 

 includes the opossum, rabbit, guinea-pig, rat, sheep, goat, cow, horse, 

 pig, raccoon, badger, dog, coyote, cat, guenon monkey, chimpanzee, 

 and man. This list we are now in a position to supplement by the 

 addition of the Australian dingo dog {Canis dingo, Blumenbach), 

 the American black bear {Ursus americanus, Pallas), the mouse 

 (Mus musculus, Linnaeus), and the elephant (Elephas indicus, Lin- 

 naeus), from which species we secured data presented in summary 

 form in Table I. 



