EFFECT OF AUTOLYSIS UPON MUSCLE CREATIN 



By Ralph Hoagland, Senior Biochemist, and C. N. McBrydE, Senior 

 Bacteriologist, Biochemic Division, Bureau of Animal Industry 1 



INTRODUCTION 



The question as to the relation between muscle creatin and urinary crea- 

 tinin is one which has been the subject of considerable investigation, par- 

 ticularly during the past few years. The importance of this problem 

 lies in the fact that it is now quite clearly established that the creatinin 

 excreted in the urine with a creatin-creatinin-free diet, is an accurate 

 measure of endogenous metabolism. In the mammalian family, creatin 

 is found chiefly in the striated muscular tissue, and to a lesser extent in 

 other tissues and in fluids. The anhydrid creatinin is present in very 

 small quantities. Since the amount of creatinin excreted in the urine 

 is an accurate measure of tissue metabolism and since creatin is a normal 

 constituent of muscular tissue, and since also there is a close chemical rela- 

 tionship between the two compounds, the natural supposition, is that 

 urinary creatinin is derived from muscle creatin. This may be said to 

 be the generally accepted view, and it is supported by considerable 

 experimental evidence; yet, on the other hand, certain investigators 

 have obtained results which do not appear to support this theory. 



The question as to where creatinin is formed in the body is another 

 problem concerning which there is considerable lack of agreement. 

 In the light of our present knowledge on the subject it must be admit- 

 ted that the method and the place of production of creatinin in the body 

 have not been clearly established. 



In the course of a series of autolytic experiments with lean beef, car- 

 ried on in connection with investigations concerning changes taking place 

 in beef in cold storage, certain changes were noted in the creatin and crea- 

 tinin content of the muscles which appear to throw some light on 

 the question as to the source and method of production of creatinin. 

 The results of these observations are offered as a contribution to our 

 knowledge of the subject. 



PREVIOUS AUTOLYTIC EXPERIMENTS 



Gottlieb and Stangassinger (3) 2 carried on an extensive series of auto- 

 lytic experiments with various organs, tissues, and fluids of dogs, cats, 

 and calves, using toluol as an antiseptic. As a result of their studies these 



1 The authors desire to extend their thanks to Mr. W. C Powiek for assistance rendered in connection 

 with the analytical work reported in this paper. 



2 Reference is made by number to " Literature cited," p. 546. 



Journal of Agricultural Research, Vol. VI, No. 14 



Dept. of Agriculture, Washington, D. C. July 3. 191° 



et A— 23 



(535) 



