NUCLEIN OR PURINE METABOLISM ?8l 



being derived from the tissue disintegration, but that it varies under 

 different conditions of nutrition as well as under different conditions of 

 activity of the body. 



There are two main conditions which give rise to a marked increase in 

 the output of endogenous uric acid. These are (1) severe muscular activity, 

 (2) febrile states accompanied by increased nitrogenous metabolism. Since 

 both these conditions are associated with an increased breakdown of muscle 

 substance we may regard the uric acid as derived especially from the 

 hypoxanthine or its precursors, such as inosinic acid, contained in the 

 muscle. 



The foods which are especially effective in causing increase in the 

 exogenous uric acid are those rich in nuclein, such as sweetbreads or liver, 



30 



m 



ttHj 

 -i-TJ-U- 



10 II 12 



FIG. 355. Curves showing the hourly excretion of uric acid and urea after a single 

 meal. (HOPKINS.) The continuous line = uric acid output ; the dotted 

 line = urea output. 



and those rich in hypoxanthine or its precursors, such as meat or meat 

 extract. 



When these foods are taken, or when nucleic acid itself is administered, a con- 

 dition of leucocytosis is generally produced, the number of leucocytes in the blood 

 being increased as much as three times. It has been suggested that the uric acid is 

 actually formed by a disintegration of the newly formed leucocytes and not by a direct 

 conversion of the purines of the food. It is quite possible, as suggested by Schittenhelm, 

 that the leucocytes play a part in the transference of the nucleins from the intestine 

 to the circulation. But the absence of any absolute proportionality between the degree 

 of leucocytosis and the amount of uric acid excreted points to the probability of a direct 

 conversion of the purines of the food into uric acid. 



URIC ACID IN GOUT 



Gout is a condition in which deposits of urate of soda occur in the cartilages of the 

 joints, the great toe joint being the seat of predilection for this disorder. The deposit 

 is generally associated with an acute inflammation of the joint. In normal individuals 

 the amount of uric acid in the blood is too small to be detected. Uric acid is readily 

 excreted by the healthy kidneys. If the production of uric acid be largely increased 

 by the administration in large quantities of food-stuffs rich in purines, it becomes 



