TRIGLYCERIDES AND FATTY ACIDS 125 



ketone bodies could be noted when isomolecular quantities of the odd- 

 carbon acids, valeric and heptanoic acids, were given. In later studies from 

 this group,^^ in which ethyl esters were fed to rats, it was found that all 

 even-chain saturated acids from C4 to Cig were ketogenic. Moreover, ethyl 

 oleate, likewise, was shown to be converted to the ketone bodies. Butyric 

 acid was found to produce a ketonuria in fasting rats which was quantita- 

 tively identical with that induced by an isomolecular amount of sodium 

 acetoacetate,'-' or by that of ethyl acetoacetate.-^ Gottschalk-^" reported 

 an experiment in which it was found that a marked ketonuria resulted from 

 the feeding of butyric acid to a man on a carbohydrate-free diet. Deuel et 

 alP were unable to demonstrate any ketogenic action when the ethyl esters 

 of any of the odd-carbon acids from C;i to Cu were fed to fasting rats. 



Embden and co-workers'' '^ demonstrated that ketone bodies originated in 

 the perfusing fluid when surviving livers of dogs were perfused with blood 

 containing caproic, caprylic, or capric acids; on the other hand, no ketosis 

 developed when odd-carbon fatty acids were added to the perfusate. These 

 results were partially confirmed by Dakin,i* who observed ketonemia after 

 caproic acid or after a number of intermediates had been added to Ringer 

 solution used to perfuse a surviving liver. 



The results with tissue slices have confirmed the in vivo tests. Thus, 

 Jowett and QuasteP- reported a marked ketone body formation by liver 

 slices which were incubated with the even-chain fatty acids. The values for 

 ketone body formation expressed as Qac (equivalent cu. mm. as gas per mg. 

 dry weight per hour) were as follows: control, 0.20; C2, 0.42; C4, 2.55; 

 Ce, 2.62; Cs, 1.80; and Cio, 1.39. The corresponding values for the odd- 

 chain fatty acids were as follows: control, 0.20; Cs, 0.12; C5, 0.51; C7, 

 0.88; and C9, 0.72. Cohen ^«- reported the occurrence of ketogenesis by 

 liver shces incubated with butyrate or caproate, but not when propionate or 

 valerate was employed. Acetate gave slightly positive results. Leloir and 

 Munoz*^ likewise demonstrated the synthesis of ketones as a result of incu- 

 bation of liver slices with the salts of even-chain fatty acids. 



Cheldelin and Beinert^^^ reported that cyclophorase produces large 

 amounts of ketone bodies from the even-numbered fatty acids, and only a 

 small quantity from odd-numl)ered acids. Thus, the acetoacetate formed 

 approaches 1 mole for the Ce acid, and exceeds this figure for octanoic acid 

 (1.5 mole). In the case of the lower odd-numbered fatty acids, the aceto- 

 acetate content is very small; in the case of the C9 and Cu acids, 0.5 mole of 

 acetoacetate is formed per mole of fatty acid oxidized. 



28" A. Gottschalk, Klin. Wochschr., 11, 978-980 (1932). 



2»i V. H. Cheldelin and H. Beinert, Biochim. et Biophys. Acta, 9, 661-673 (1952). 



