6o6 



PHYSIOLOGICAL CHEMISTRY 



1 6. A Study of Endogenous Uric Acid Output.- The uric acid in the 

 urine is said to have two sources, i.e., from the purine material of the 

 tissues and from the purine material ingested. The former is endogenous 

 uric acid, the latter exogenous uric acid. 1 The output of uric acid 

 on the purine-free diet in Experiments 15 and 17 is endogenous. 



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FIG. 1 90. INFLUENCE OF PROTEIN INGESTION ON ENDOGENOUS URIC ACID OUTPUT. 

 GLUTEN (130 GRAMS) INGESTED AT i P.M. (Mendel & Stehle: Jour. BioL Chem., 22, 215, 



Mares 2 claims that food-stuffs act to increase the endogenous uric 

 acid output by stimulating the digestive glands to activity. A 

 similar finding is reported by Mendel and Stehle. 3 The food-stuff 

 having the most pronounced influence was protein. Pilocarpine 

 which stimulates the digestive glands was found to increase the endog- 

 enous uric acid output whereas atr opine which inhibits secretory 

 activity was found to decrease the output of endogenous uric acid. 



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FIG. 191. THE ENDOGENOUS URIC ACID OUTPUT DURING FASTING. (Mende & Stehle: 

 Jour. BioL Chem., 22, 215, 1915.) 



The influence of protein upon the endogenous uric acid excretion is 

 shown by the chart in Fig. 190. The fasting output by the same 

 individual is shown, for comparison, in Fig. 191. 



Experiment. Ingest a purine-free diet consisting of milk, egg, fruit, cheese, 

 butter, sugar and bread for one day. Continue the diet for breakfast and lunch- 

 eon the next day but eat nothing after 12 o'clock noon, until 12 o'clock noon the 



1 Burian and Schur: Zeit. physiol. Chem., 43, 532, 1904-5. 



1 Mares: Arch. f. d. ges. Physiol., 134, 59, 1910. 



1 Mendel and Stehle: Jour. BioL Chem., 22, 215, 1915. 



