Is Glycogen the Source of Acids? 247 





Initial. 



24 Hours. 



Eleven Days. 





3.8 C.C. 



5 25 C.C. 



9.00 C.C. 





6.42 



7.00 



6.O4 



II 



3.60 C.C. 



6.50 C.C. 



10.60 C.C. 



p »- 



6.60 



6.77 



5-79 



At the end of the period (eleven days), the remaining glycogen, 

 if any, was sought and it was found that 13 milligrams computed 

 as glucose from Benedict determinations on the hydrolyzed (acid) 

 nitrates, remained of the gram introduced, at the beginning. 



Discussion. — It is evident from the results of the experiment 

 that we may look to glycogen as one of the precursors of substances 

 concerned with the development of acidity in autolyzing tissues. 

 These substances are probably hydroxy acids, such as lactic and 

 keto-acids, such as pyruvic. Obviously, it is possible for such 

 acids to form from other sources, as for instance, from the carbo- 

 hydrate moiety of nucleosides, from the deaminized residue of 

 amino-acids and doubtless neutral fats and phospholipines like- 

 wise may contribute. The interest in glycogen for the writer 

 centers about the increased metabolism at the inception of starva- 

 tion. A well-fed guinea pig will exhibit a sudden increase in 

 amino-nitrogen when its carbohydrate food is limited or replaced 

 by nitrogenous diet. The disappearance of glycogen from the 

 liver is remarkably fast. Thus a guinea pig whose diet had been 

 controlled from February 16 to February 23, having been given a 

 full carbohydrate diet during this period was permitted to starve 

 three days and an examination of the liver showed the complete 

 absence of glycogen. The fat of the pig does not seem to change 

 correspondingly with the change in diet and the suggestion is made 

 that the rapid rise in nitrogenous excretion, expecially of amino- 

 nitrogen may be due to the contribution of glycogen to the increase 

 in hydrogen ion concentration with the concomitant appearance 

 of the optimum reaction for tissue enzyme action which Dernby 

 has shown to occur. Intra vitam autolysis then proceeds. 



Aside from the reports of Bradley, Dernby and of the present 

 writer, this phase of the dynamics of tissue enzyme action does not 

 seem to have been examined. 



References. 



Bradley, H. C. J. Biol. Chem., 1916, xxv, 201. 



Dernby, K. G. Biochemisch. Z., 1917, lxxxi, 107; J. Biol. Chem., 1918, xxxv, 179. 

 Morse, W. J. Biol. Chem., 1917, xxx, 197. 



