154 III. OXIDATION AND METABOLISM 



creatized dogs with markedly increased fat metabolism caused by exercise 

 or by the administration of dinitrophenol. 



(6) Age as a Factor in Ketonuria. It is generally considered that very 

 young animals are more susceptible to ketosis than are older animals. 

 Moreover, the severity of the ketosis is greater in the young. Peters and 

 Van Slyke^^* are of the opinion that this phenomenon may be traced to the 

 greater rapidity with which the glycogen stores are expended in the young 

 than in older individuals. ^^^■*^'' 



On the other hand, Knodt and associates^^^ reported a progressive rise in 

 the blood acetone values from birth to maturity. Their data are sum- 

 marized in Table 4. 



Table 4 



Comparison of Blood and Urinary Acetone Bodies 

 OF Various Age Groups of Cattle" 



" Adapted from C. B. Knodt, J. C. Shaw, and G. C. White, /. Dairy Sci., 25, 861-867 

 (1942). 



Although no information is available as to the effect of age on the result- 

 ing ketonuria in the rat, some data on comparative liver glycogen are sug- 

 gestive. Thus, it was shown^^- that the level of glycogen in the livers of 

 unfasted rats is highest at thirty-nine to forty days, under which circum- 

 stances it exceeds 8%. From this value, it was found to decrease gradually 



«9 1. A. Mirsky and W. E. Nelson, Am. J. Diseases Children, 67, 100-105 (1944). 



^ I. A. Mirsky, M. Korenberg, N. Nelson, and W. E. Nelson, Endocrinology, 28, 

 358-367 (1941). 



«i C. B. Knodt, J. C. Shaw, and G. C. White, ./. Dairy Sci., 25, 861-867 (1942). 



«2 H. J. Deuel, Jr., J. S. Butts, L. F. Hallman, S. Murray, and H. D. Blunden, J. Biol. 

 Chem., 119, 617-620 (1937). 



