TRIGLYCERIDES AND FATTY ACIDS 193 



the composition of the liver fatty acids closely resembles that of the fatty 

 acids in depot fat.^"-®^^-^™ When minimal quantities of fat are present in 

 the diet, the liver is the first organ to show fat synthesis. Artom®^"* and 

 Artom and Peretti^''^ consider that the increase in phospholipids in the 

 liver during the absorption of ingested neutral fats may be interpreted as 

 proof of the participation of the liver in the hitermediate metabolism and 

 transport of the fatty acids. Bernhard and Schoenheimer®^^ demonstrated 

 that, although the composition of liver lipids changes more promptly than 

 do the fat depots, all storage tissues ultimately exhibit similar changes. 

 Whereas a 50% turnover of liver fatty acids occurred within one day in the 

 case of mice, a longer interval was required for a comparable change in the 

 fat depots."^ 



(c) Ketone Body Formation in the Liver. Another indication that the 

 liver occupies a miique position in fat oxidation is the fact that it is the 

 principal organ which is capable of ketone body formation. Thus, after 

 perfusion of various organs, Embden et alJ ■'"^^''"^^ and Snapper and co- 

 workers '^^^''"^ reported that only the li^'er formed appreciable quantities of 

 ketone bodies, while skeletal muscles, kidney, and Imig did not bring about a 

 corresponding synthesis. This exclusive ketogenic capacity on the part of 

 the liver w^as fomid to be true not only in the normal organ but also in 

 pathologic conditions following pancreatectomy and phlorliizin poisoning. 

 In these cases the production of ketone bodies was considerably increased.^*- 

 Moreover, Himwich and associates^^^'^^^ demonstrated that the organs of 

 the dog, except the liver, removed ketone bodies from the blood, while an 

 increased amount w^as present in the venous blood coming from the liver, 

 as contrasted with that in its arterial supply. Mirsky^^^ showed that the 

 Uver is required for the production of ketosis by anterior pituitary extract. 

 Although Jowett and QuasteP-'^^ did note that small amounts of ketone 

 bodies were formed from butyric acid by slices of spleen, testes, and kidney, 

 in the presence of added fatty acids, the quantities produced by liver slices 

 were ten to forty times as great. Harrison and Long^^^ reported that, when 

 ketosis was produced in the intact rat by fasting, by phlorhizin, or by the 

 injection of anterior pituitary extract, a large amomit of ketone bodies was 

 present in the liver, while none appeared in the muscle mitil the level of 

 ketone bodies in the plasma had reached approximately 70 mg. %. An- 

 other indication of the hepatic origin of the ketone bodies is e\adent from the 



«" C. Artom and G. Peretti, Arch, intern. physioL, 36, 351-370 (1933). 

 «"K. Bernhard and R. Schoenheimer, /. Biol. Chem., 133, 713-720 (1940). 

 «"^I. A. Mirsky, A?n. J. Physiol., 116, 110-111 (1936). 



