EXPERIMENTAL DIABETES 381 



Confirmation of the possibility of such a process is further found 

 in the ease with which dextrose can be converted into lactic 

 acid, for example, during the action of zymase (G. Buchner) : 

 C 6 H 12 6 = 2C 3 H 6 C 3 . 



In the laboratory, then, we see that the conversion of alanin 

 into dextrose is quite possible, and that, as an intermediate product, 

 lactic acid is formed. By biological experiment, equally con- 

 vincing results have been obtained by Langstein and Neuberg ( 2 ). 

 Those workers starved rabbits for eleven days by which time, as 

 we have seen above, the tissues will be pretty well cleared of 

 glycogen and then fed them with 20-30 grm. of alanin ; on killing 

 the animals shortly afterwards, 2 grm. of glycogen were found in 

 the liver, an amount greater than could possibly have been de- 

 posited had the alanin acted merely as a pseudo-glycogen former. 

 Moreover, and this is the most convincing result of all, the 

 urine contained lactic acid in considerable amount. That this 

 lactic acid had actually come from the alanin, and not from 

 the tissues of the animal, was shown by the fact that the ad- 

 ministration of the oxyphenyl compound of alanin, namely, tyrosin 

 (oxyphenyl-amido-propionic acid), was followed by the excretion 

 in the urine of oxyphenyl-lactic acid. Kraus ( 2 ), as we have 

 stated above, also found that cats, when starved and poisoned 

 with phloridzin, excreted much more sugar when alanin was 

 given them than when no alanin was given. 



With regard to amido -acids containing six carbon atoms, if 

 we place side by side the formula of leucin the representative 

 of this class and that of dextrose, we shall see that no very 

 great rearrangement of atoms would be necessary to convert 

 the former into the latter body. Leucin is iso-butyl amido- 

 acetic acid, and has the formula : 



COOH-CHNH 2 -CH 2 CH 



CH 3 



dextrose has the formula CH 2 OH - (CHOH) 4 CHO, and although 

 the transformation would involve the production of a straight 

 chain of carbon atoms out of one which is branched i.e. of a 

 normal out of an m>-compound a process which is rarely met 

 with in organic chemistry there can be no denial on a priori 



