382 THE METABOLISM OF THE CARBOHYDRATES 



grounds of the possibility of the transformation. In fact, F. 

 Mliller has shown that by the action of KOH on dextrose, tetra- 

 oxy-caproic acid 



CH 2 OH - (CHOH) 2 - COH 



COOH 



is formed, and this contains a branched chain. 



The recent discovery by Orgler and Neuberg that tetra- 

 oxyamin caproic acid is produced from chondrosin by the action 

 of baryta on it, furnishes us with direct chemical evidence of 

 the possibility of sugar production from leucin, as is shown by 

 the following equations : 



COOH 



CHNH 2 



CH 2 



CH 



I \ 

 CH 3 CH 



(Leucin] 



CH 2 OH 

 CHNHo 



CHOH 



I 

 CHOH? 



CH Q COOH 



CH 2 OH 



C'HOH 



CHOH 



I 



COH 



I \ 

 CH, COOH 



( T extra- oxyamin (Saech aric acid) 

 caproic acid) 



CH 2 OH 



CHOH 



I 

 CHOH 



CHOH 

 CHOH 



CHO 



(Dextrose) 



The evidence that leucin may form sugar in the animal 

 body is by no means so convincing as the chemical results which 

 we have just been considering might lead us to expect. Thus, 

 Halsey ( 38 ) did not find any increase in the sugar excretion to 

 follow leucin ingestion in dogs rendered diabetic by phloridzin ; 

 and feeding animals with proteids which yield much leucin has not 

 been found, by various workers, to increase the glycogen deposits 

 any more than do other proteids. On the other hand, Mohr has 

 recently obtained positive evidence in a case of severe adolescent 

 diabetes in man. The patient was for some time on a constant 

 diet during which the daily sugar excretion varied only between 

 49 and 63 grm. By adding 20 grm. leucin, obtained from a 

 pancreatic digest, to the diet, the sugar excretion rose to 72-75 

 grm., sinking again to 55-59 grm. after the leucin feeding was 

 stopped. 



