REGULATION OF CELL ACTIVITIES 197 



Levene and Meyer have pointed out that the disappearance 

 of sugar is not necessarily due to destruction of sugar, but 

 that the sugar may. have been condensed into a disaccharide 

 or polysaccharide.* 



GLYCOSURIA 



Removal of the pancreas produces an excretion of 

 sugar in the urine which has been shown to be due to the 

 absence of some chemical substance, as it is not due to nervous 

 action. There is always a small amount of sugar in the blood 

 (0-1-0-15 P er cent.) and a trace of sugar in the urine, but under 

 certain conditions the amount of sugar in the urine becomes 

 increased. The excretion of sugar seems to be accompanied by 

 an inability of the body to utilise sugar, and sugar seems to 

 be formed from many other substances. Glycosuria has two 

 important bearings. First, the disease diabetes is character- 

 ised by glycosuria, in which large quantities of sugar are lost 

 in the urine. Even if large quantities of food are taken the 

 body becomes wasted owing to the conversion of fat and 

 proteins to sugar, hence these substances are lost from the 

 body. In advanced stages the excessive decomposition of 

 fats leads to the excretion of " acetone " bodies in the urine. 

 The aceto-acetic acid and jS-hydroxybutyric acid cause an 

 increased excretion of ammonia and fixed bases in the urine. 

 Coma and death may result from removal of the bases 

 potassium and sodium. The second important point about 

 glycosuria is that various forms of experimental glycosuria 

 are used to show the conversion of other substances into 

 carbohydrate (p. 107). 



Removal of the pancreas does not produce glycosuria 

 owing to the absence of its external secretion because block- 

 ing the duct or diverting the external secretion from the 

 intestine does not produce glycosuria. 



In addition to removal of the pancreas, after which there 

 is an increase in the amount of sugar in the blood, there are 

 several other ways in which glycosuria can be produced. 



Alimentary Glycosuria. If the amount of sugar is increased 

 in the blood the kidney excretes a greatly increased amount of 

 sugar in the urine. This increase of sugar in the blood has 

 been mentioned above as the cause of glycosuria after removal 

 of the pancreas. If large quantities of carbohydrate are 

 given by the mouth there is an increased absorption of sugar 

 into the blood. If more sugar is absorbed than can be removed 

 by the liver the excess of sugar passes into the general circula- 



* P. A. Levene and G. M. Meyer, Journ. BioL Chem., ign.vol. 9, p. 97. 



