4 6 



Scientific Proceedings (62). 



28 (960) 



Atrophy does not involve acceleration of tissue enzyme action. 

 By Max Morse. 



[From the Department of Physiology, University of Wisconsin.] 



The thesis that atrophy, such as occurs in normal involutionary 

 tissue absorption, in muscle whose nerve supply has been severed, 

 etc., involves a change either in autolytic enzyme content or in its 

 activation, is not supported by experiments of the writer. It has 

 been shown by him 1 that in the larval frog, where, during meta- 

 morphosis extensive atrophy occurs, the histological picture re- 

 sembles closely those of polymyositis, dermatomyositis, etc., as 

 described by Striimpell, Jacoby, Steiner, et al., and that in the 

 case of this amphibian, there is no acceleration of autolysis in vivo 

 nor in vitro and where thyroid is used to accelerate metamorphosis, 

 as Gudernatsch first showed, the time of completion of the process 

 is reduced two thirds; even in this case, there is no change in 

 rate of autolysis. In another set of experiments, the left sciatic 

 of a rabbit was cut under asepsis, the wound healing, as far as it 

 was permitted to go, without bacterial interference; after a week, 

 the muscles affected were compared as to power for autolysis 

 in vitro after the method of Salkowski and here, again, no accelera- 

 tion of rate of enzyme action was determined. 



I know of but a few citations in biochemical literature to 

 investigations along these lines. All of these 2 seem to bear out 

 the same conclusion. Grund, for instance, in an experiment 

 similar to the one above, found the ratio residual nitrogen to total 

 nitrogen to be less than one, and while residual nitrogen involves 

 more than products of hydrolysis of muscle proteins, yet the point 

 is significant; at least there is no increase in tannic acid non- 

 precipitable nitrogen as one would certainly postulate if autolysis 

 is increased in atrophying muscle. 



The hypothesis is advanced that in atrophying tissue some 



1 Proc. this society, 1912 and 1913; Amer. Journ. Physiol., 36, p. 1, 1915; 

 Journal Biol. Chemistry, 19, p. 421, 1914. 



2 Rumpf und Schumm, Deutsch. Zeitschr. fur Nervenheilk., 20, p. 445; Deulsch. 

 Arch, fur klin. Med., 79, p. 158; Grund, Arch.f. exper. Path, und Pharmak., 67, p. 393. 



