SUGAR FORMATION FROM FATS. 413 



indicate the same, namely, that in phlorhizin diabetes after the disap- 

 pearance of the liver-glycogen the fat which migrates to the liver serves 

 as material for the formation of sugar (PFLUGER). These observations 

 make the formation of sugar from fat highly probable and the same is true 

 for the observations of JuNKERSDORF. 1 He found that in an animal made 

 glycogen free, by starvation and with phlorhizin poisoning, that toward 

 death, the nitrogen as well as the sugar elimination increased but that 

 the D : N ratio was higher than with the sugar formation from protein 

 alone. His calculations are not free from exception. 



On the other hand there are many observations on animals and 

 also clinical observations which oppose the theory of the formation 

 of sugar from fat in diabetes. LUSK found in a dog with phlorhizin 

 diabetes that the quotient D:N = 3.65:1 was not changed on feeding fat, 

 and he has published further results of experiments 2 which show that 

 active muscular work, which strongly increases the fat decomposition, 

 does not change the quotient in dogs with phlorhizin diabetes. It is 

 difficult to draw positive conclusions from these experiments, still LUSK 

 seems to deny the formation of sugar from fat. 



Attempts have been made to solve the question as to the material 

 from which sugar is formed by the determination of the respiratory 

 quotient and comparing this with the quotient D:N. The calculations 

 in this direction have not led to positive results. 3 As the quotient D : N 

 is not an accurate measure of the quantity of sugar formed, and as we, 

 as yet, do not know the quantity of oxygen necessary to form sugar 

 from protein, HAMMARSTEN believes that it is just as impossible to con- 

 clude from the respiratory quotient that sugar is formed from the fats 

 as from the proteins. 



We have no complete proofs for the formation of sugar from fat, still 

 we can indicate the probable proofs therefor. There is really no objec- 

 tion from a theoretical standpoint to the assumption that the body has 

 the power of producing sugar from protein as well as from fat, and such 

 a power does not seem improbable. 



As a formation of sugar from protein is now generally considered as 

 proved, it follows that the protein can yield material for the formation 

 of glycogen and that it is a true glycogen-former. PFLUGER and JUNKERS- 

 DORF 4 have given direct proof for this. They fed a dog, which had 

 previously been made glycogen-free by starvation and phlorhizin injec- 



1 Pfliiger's Arch., 137. 



2 Amer. Journ. of Physiol., 22. 



3 Magnus-Levy, Zeitschr. f. klin. Med., 56; Pfliiger's Arch., 108; Mohr, Zeitschr. 

 f. exp. Path. u. Therap., 4. 



4 Pfluger's Arch., 131. 



