THEORIES AS TO CAUSE OF PANCREATIC DIABETES 529 



is used as an argument that it is not as sugar that the cells 

 utilize carbohydrates, but as glycogen. In the words of v. 

 Noorden, the natural carbohydrate food of the cell is not glucose, 

 but glycogen. 



Pfliiger takes, as the more probable, the view that it is excessive 

 conversion of glycogen into sugar, rather than defective glyco- 

 genesis, that is at fault. The function of the pancreas, on this 

 basis, is the formation of an anti-enzyme that holds in check 

 the diastatic enzyme of the cells. Pavy maintains that after 

 sugar is once built up into glycogen it goes on to form fats and 

 proteids, but does not again break down into sugar under 

 normal conditions. This view, in direct opposition to Bernard's 

 theories of carbohydrate metabolism, is not generally accepted. 



Theories as to the Cause of Pancreatic Diabetes 

 With the existing confusion and difference of opinion concern- 

 ing the importance of defective glycogen formation in diabetes, 

 it is impossible to give an exact or clear idea concerning the 

 role of the pancreas in diabetes. Certainly, after pancreas ex- 

 tirpation the liver does not entirely lose its power to form 

 glycogen, for some glycogen may be still present in the liver 

 after the most protracted glycosuria. Neither does defective 

 glycogenesis explain why the blood of starving pancreatec- 

 tomized animals contains excessive quantities of sugar. This 

 last fact speaks rather in favor of excessive breaking down of 

 the glycogen, analogous to the glycosuria following puncture of 

 the medulla. Possibly, either the glycolytic ferments or the 

 glycogen are normally so combined in the cells that they cannot 

 freely act or be acted upon to form sugar, which combined con- 

 dition ceases to exist in the absence of the internal secretion of 

 the pancreas. This is, of course, purely hypothetical. 



There can be no doubt that the tissue-cells of pancreatec- 

 tomized animals have lost their power to utilize sugar, leaving 

 out of the question whether this is due to abnormal glycogenesis 

 or to loss of glycolytic power. Feeding of carbohydrate food 

 causes immediately an increase in the amount of sugar excretion, 

 and usually the greater part of the sugar appears again in the 

 urine, showing that it has passed through the body unutilized. 

 Levulose alone seems to be fairly utilized under these conditions. 

 This failure to use the sugar is not due to a decrease in the 

 oxidizing powers of the cells, for other substances seem to be 

 oxidized with quite normal activity. Lactic acid, inosite, man- 

 nite, benzol, and many other substances, when given by mouth, 

 are oxidized as in normal animals. The respiratory quotient is 

 affected only as far as the loss of carbohydrates reduces the sum 



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