FASTING STUDIES 

 II. A note on the composition of muscle from fasting dogs^ 



H. C. BIDDLE AND PAUL E. HOWE 



(Laboratory of Physiological Cheniistry, University of Illinois, 



Urhana, Illinois) 



The variations in the composition of the different forms of 

 muscle in the normal individual have received considerable atten- 

 tion. A comparison of the nitrogen and moisture contents of heart 

 and striated muscle reveals a lower percentage of nitrogen and a 

 higher percentage of moisture in the heart muscle than in the skeletal 

 muscle. The proportions of these and other constituents in the 

 fasting muscle have not been studied extensively. The changes 

 which occur in the composition of muscle during fasting are 

 significant for the Solution of general problems relating to the 

 effects of fasting. 



In a study of the influence of fasting upon the creatine content 

 of dog muscle, determinations were made of the proportions of 

 nitrogen, moisture, fat and creatine in normal and fasting muscle ; 

 and also of the nitrogen and creatine in heart muscle. In these 

 preliminary experiments particular attention was paid to the per- 

 centages of nitrogen and creatine : an attempt was made to show the 

 relation between the nitrogen and creatine contents of muscle, so 

 that the ratio of creatine-nitrogen to total nitrogen might be used as 

 an index of the changes due to pathological conditions. This factor 

 should be more significant than the percentage of creatine in fresh 

 muscle, and as accurate as that for the creatine content in muscle 

 on a fat- and moisture-free basis. These results, as well as the 

 variations in the creatine content of muscle, will be discussed in a 

 later paper.^ 



^ Presented before the Columbia University Biochemical Association, 

 December 6, 1912; Biochemical Bulletin, 1913, ii, p. 288. 



^Howe and Hawk: Presented before the recent annual meeting of the 

 American Physiological Society, but not abstracted in the proceedings. 



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