212 IV. CONVERSION OF FAT TO CARBOHYDRATE 



isotope technics, on the question of the transformation of fat to carbohydrate. 

 Some of these, but not all,^-'^'^" support the Lusk viewpoint. The more 

 recent summaries on this subject include those of Bloch,^i of Deuel and 

 Morehouse, ^2 of Abraham, Chaikoff, and Hassid,^' and of Strisower, Chai- 

 koff, and Weinman.^* 



1. The Transformation of Glycerol to Glucose 



(1) Qualitative Studies 



There has been considerable confirmatory evidence, based upon qualita- 

 tive tests, indicating the transformation of glycerol to glucose. For ex- 

 ample, it was early reported that glycerol decreases the ketonuria in dia- 

 betic patients ;^^'"^'' Shapiro'^ amply confirmed this finding in the exogenous 

 ketonuria of rats, produced by the administration of sodium acetoacetate to 

 the fasting animals. Moreover, Voegtlin and associates'^ observed that 

 glycerol is an effective agent in relieving the hypoglycemic convulsions pro- 

 duced by the injection of overdosages of insulin. 



In the more direct approach to the problem, a number of investigators'^-^'' 

 conclusively demonstrated that glycerol can serve as a glycogenic agent in 

 rats when fed as the free alcohol. However, it has not been possible to 

 demonstrate glycogenesis as conclusively when glycerol is fed as a component 

 of natural fat, to rats.^'--- This discrepancy can readily be explained by the 

 fact that only 10% of the triglyceride molecule is glycerol, so that it is dif- 

 ficult to administer comparable doses of the alcohol when it is fed as a com- 

 ponent of neutral fat. Moreover, the presence of fat in the gastrointestinal 

 tract delays absorption, as compared with that noted when free glycerol is 



11 K. Bloch, Physiol. Revs., 27, 574-620 (1947). 



1^ H. J. Deuel, Jr., and M. G. Morehouse, Advances in Carbohydrate Chem., 2, 119- 

 160(1946). 



" S. Abraham, I. L. Chaikoff, and W. Z. Hassid, /. Biol. Chem., 195, 567-581 (1952). 



1^ E. H. Strisower, I. L. Chaikoff, and E. O. Weinman, J. Biol. Chem., 192, 453-463 

 (1951). 



16 F. Hirschfeld, Z. klin, Med., 28, 176-209 (1895). 



i« G. Satta, Beitr. chem. Physiol. Pathol, 6, 376-391 (1905). 



I'' R. M. Lang, Biochem. J., 9, 456-478 (1915). 



18 1. Shapiro, /. Biol. Chem., 108, 373-387 (1935). 



" C. Voegtlin, E. R. Dunn, and J. W. Thompson, Am.. J. Physiol, 71, 574-582 

 (1924-1925). 



20 L. F. Catron and H. B. Lewis, /. Biol Chem., 84, 553-559 (1929). 



21 H. J. Deuel, Jr., J. S. Butts, L. F. Hallman, and C. H. Cutler, J. Biol Chem., 112, 

 15-23(1935-1936). 



" H. J. Deuel, Jr., J. S. Butts, H. Blunden, C. H. Cutler, and L. Knott, /. Biol 

 Chem., 117, 119-129 (1937). 



