TRIGLYCERIDES AND FATTY ACIDS 175 



increased urinary excretion of inorganic sulfate, that a major portion of 

 the amino a(dd had been absorbed and metabolized. The discrepancy 

 between the dog and the rat experiments may be due to a species difference, 

 to a variation in the metabolism of cystine and cysteine, or, as seems more 

 probable, to a conversion of cysteine to serine in the Dakin experiments, 

 due to the action of the alkali used to dissolve the amino acid. 



The investigation of the role of alcohol in ketotic rats has been extended 

 by Deuel, Hallman, and Murray. ^^^ In the latter tests, a comparison was 

 made of the ketonuria produced experimentally by the exogenous or endog- 

 enous method, when isodynamic quantities of D-glucose or ethyl alcohol 

 were fed to rats. If the antiketogenesis theory is correct, any fat- 

 sparing substance should reduce the ketonuria as effectively as an equiva- 

 lent amount of glucose or of glucose precursors. According to the review 

 of Carpenter, "■' there is preponderant evidence not only that alcohol can 

 be used as a general source of energy, but also that it can serve specifically 

 as a source of energy for muscle contraction. 



In the rat experiments in which sodium butyrate was fed to produce the 

 exogenous ketonuria, ^^^ the average ketonuria per 100 gm. rat per day was 

 118.G mg. in the control group, 26.3 mg. in the group fed 100 mg. D-glucose 

 in addition to the butyrate, and 108.9 mg. in the case of the rats receiving 

 the butyrate and also an amount of ethyl alcohol isodynamic with 100 mg. 

 of glucose. In the tests in which endogenous ketonuria was employed, 

 the average ketonuria was 57.9 mg./lOO g. daily in the control group, 

 8.0 mg./lOO g. daily in the group receiving 100 mg. of glucose each day, 

 and 53 mg./lOO g. daily in the alcohol-fed group. The amount of carbo- 

 hydrate required to abolish the ketonuria almost completely is equivalent 

 isodynamically to only a fraction of the fat broken down. The authors 

 calculated that the fat utilized in the above tests amounted to 2464 mg. 

 (control group), 2407 mg. (o-glucose-fed group) and 2392 mg. (alcohol-fed 

 group). Thus, the ketone body excretion of the control group was de- 

 creased 93% by an amount of glucose dynamically equivalent to only 

 2.3% of the total fat catabolized. Similar conclusions were reached in the 

 case of fasting ketonuria in man when D-galactose was fed.^^^ Thus, it 

 was demonstrated that ketonuria was practically abolished by an amount 

 of glucose too small to alter the fat metabolism to any significant degree. 

 These experiments strongly support the ketolysis theory. 



e'. The Effect of Glucose on the Exogenous Ketonuria of Rats: The 

 experiments cited in the previous section on endogenous ketonuria indicate 

 that ketone bodies disappear from the urine as the result of the adminis- 



"3 T. M. Carpenter, J. Nutrition, 6, 205-224 (1933). 



