OLYCOGEN. 373 



ablj derived from this source exclusively, there is evidence to show 

 that it may be formed from the albumins as well. If animals are 

 allowed to starve until the entire reserve of glycogen has been con- 

 sumed, and they are then fed on albumins exclusively, it will be 

 observed that a gradual deposition of glycogen occurs nevertheless, 

 which can be referable only to the ingested albumins. In the severer 

 forms of diabetes, moreover, as will be shown later, sugar appears 

 in the urine although all carbohydrates are excluded from the 

 diet. If then in such cases the nitrogenous metabolism is diminished 

 as much as possible by reducing the albumins of the food to a mini- 

 mum, and a day of fasting is further introduced into the regime, or 

 when diarrhoea occurs, the amount of sugar that appears in the urine 

 is notably reduced. If, on the other hand, the amount of albumin 

 in the food is increased, an increased elimination of sugar occurs , 

 the parallelism between the elimination of nitrogen and sugar may 

 then be quite remarkable. At times the ratio of nitrogen to sugar 

 has been found to be 1 : 3 to 1:4. Similar conditions prevail in 

 cases of experimental diabetes following extirpation of the pancreas 

 or poisoning by phloridzin. 



The manner in which the glycogen, viz., the glucose, is formed 

 under such conditions has long been a matter of speculation. That 

 the carbohydrate group of the albumins does not play an important 

 role in this connection is apparent at once, as the amount is far too 

 small to account for the large amount of glucose, which may still be 

 eliminated in the urine in severe diabetes at a time when no carbo- 

 hydrates are administered in the food. Benedix, moreover, has 

 shown that in dogs which are fed on casein (in which a carbohydrate 

 group does not exist) glycogen is nevertheless stored in the liver in 

 notable amounts. Under such circumstances the leucin complex 

 may be the source of the glucose, with the intermediate formation 

 of oxy-capronic acid. This possibility has been suggested by Miiller, 

 Seeman, and Cohn. Opposed to this view is the fact that the leucin 

 of the tissues contains a divided chain of carbon atoms, being the 

 isobutyl-amido-capronic acid. But, on the other hand, Miiller has 

 pointed out the readiness with which glucose, with its uninterrupted 

 chain, will pass over into tetraoxy-capronic acid on standing in con- 

 tact with calcium hydrate. This latter has a divided chain, and we 

 can thus imagine perfectly well that the reverse also can happen. 



This view accords well with Folin's teaching that the ami no- 

 group of the amino-acids which are liberated during pancreatic 

 digestion is split off in the liver, and that the remaining acid radi- 

 cles are stored as glycogen or as fat. 



Whether or not the fats also can give rise to the formation of 

 glycogen has not been established beyond doubt. It seems, however, 

 that this does not occur. Luttje has thus shown in a severe case of 

 diabetes that while the patient eliminated 60 grammes of nitrogen 

 and 112 grammes of sugar while receiving 400 grammes of nutrose, 

 the nitrogen fell to 9.9 grammes and the sugar disappeared alto- 



