228 IV. CONVERSION OF FAT TO CARBOHYDRATE 



scribed this condition as occurring when the metaboHc processes were 

 "caught off balance." 



Lusk^ reported an R.Q. of 0.687 in a fasting phlorhizinized dog. In 

 Joshn's series of 113 diabetics, ^"^ only eighteen tests on nine subjects ex- 

 hibited an R.Q. figure below 0.70. In the evaluation of the low R.Q. figures 

 cited by DuBois/^ Richardson^ noted that values below 0.65 were in the 

 minority, the lowest figure being 0.64. It is not considered that even the 

 lowest authenticated value represents a situation in which fat is being trans- 

 formed to carbohydrate. Stewart, Gaddie, and Dunlop,^"'' likewise, were 

 unable to obtain any evidence, based upon changes in R.Q., for the con- 

 version of fat to carbohydrate in human subjects undergoing exercise. The 

 results of Hawley^"^ on phlorhizin-diabetic dogs, also, offered no evidence of 

 a conversion of fat to carbohydrate under the influence of insulin. 



Thus, no convincing data based upon R.Q. are available. The number of 

 authentic values for the non-protein R.Q. which are below the 0.707 are 

 limited, and these are readily explained by the reduction of the protein 

 R.Q., as a result of an incomplete oxidation of the carbohydrate moiety, and 

 of the fat R.Q., which would be attributable to the loss of some of the fat 

 molecule as ketone bodies in the urine. Either changes in acid-base balance 

 or technical difficulties in analyses may also cause the low R.Q. observed in 

 some experiments. 



(3) The Importance of Epinephrine 



One classical viewpoint as to the cause of glycosuria in diabetes was ex- 

 pressed by Eppinger, Falta, and Rudinger. ^"^ The phenomenon is attrib- 

 uted to an overproduction of carbohydrate from fat, and this was believed 

 to result from an increased stimulation of adrenal secretion. The latter 

 would inhibit insulin production. As evidence for this theory, these in- 

 vestigators^°* cite the largely increased sugar output in depancreatized dogs 

 when epinephrine is administered. 



However, a number of workers have been unable to confirm the in- 

 creased glycosuria which would have followed epinephrine injection if the 

 carbohydrate stores had been removed prior to the administration of the 



1"^ E. P. Joslin, Diabetic Metabolism with High and Loiv Diets, Carnegie Inst. (Wash- 

 ington), Publ. No. 323, 1923. 



i" C. P. Stewart, R. Gaddie, and D. M. Dunlop, Biochem. J., 25, 733-748 (1931). 



los E. E. Hawley, Am. J. Physiol., 101, 185-193 (1932). 



i»9 H. Eppinger, W. Falta, and C. Rudinger, Z. klin. Med., 66, 1-52 (1908). 



