THE GLYCOGENIC FUNCTION. 



BV C. M. BROOM ALL. 



The function of sugar in the animal economy is recognized 

 to be that of an energy producer. Its round of action briefly 

 stated is as follows : The carbohydrates taken in as food are 

 transformed in the intestines into glucose. This is absorbed 

 and taken by the portal vein to the liver. Here the glucose is 

 converted into glycogen and kept in store in that shape. 

 When energ>^ for heat or muscular effort is needed, the gly- 

 cogen is reconverted into glucose, transported to the tissues, 

 and there " burned " to supply the required energy. Such of 

 this sugar as is not oxidized is stored away as glycogen in the 

 muscles, to be subsequently reconverted into sugar for fuel 

 at the proper time. It is seen, therefore, that both the liver 

 and muscles act as storehouses of potential energy. 



If in the food there is an excess of carbohydrates, more 

 than the liver and muscles can store away as glycogen, a 

 portion of the glucose will appear in the blood. This sugar 

 will be excreted by the kidneys, constituting physiological dia- 

 betes. There is nothing abnormal in this, and it is simply the 

 result of overloading the sj'Stem with carbohydrate foodstuff. 



If, on the other hand, sugar appears in the urine under 

 normal food supply, then we ma}' rightly suspect some patho- 

 logical process. Under such circumstances it is usual to con- 

 sider the liver at fault. In a large number of cases of patho- 

 logical diabetes mellitus, however, there is found an accom- 

 panying disease of the pancreas. It is concluded, therefore, 

 that the pancreas may also have something to do with diabetes 

 and there seems to be a general trend of opinion to the effect 

 that the pancreas produces an internal secretion in some way 

 intimately associated with the metabolism of sugar in the body. 



The foregoing outlines, in few words, practically all that 

 is known concerning the function of glycogen in the human 

 econoni}'. The facts, however, do not appear to have been 

 correlated with other branches of science in such a way as to 



