LIPIDS PRESENT IN LIVER 725 



that adrenalectomy abolishes the sex differences in ketonuria. 152 However, 

 adrenocortical extracts are not able to provoke a ketonuria when injected 

 into fasting rats. 153 



f. The Effect of Diet on Liver Lipids. The liver lipids are more suscep- 

 tible to alteration than are those in the several fat depots. Thus, they 

 rapidly assume the character of the food fats during alimentation, and 

 they likewise mirror the composition of the storage fats during periods of 

 inanition. 



In 1910, Joannovics and Pick 154 demonstrated that the iodine numbers of 

 the liver phospholipids increased from 100 to 150 within a few hours after 

 the feeding of the highly unsaturated cod-liver oil. Differences in the io- 

 dine values of liver phospholipids were found when coconut oil 155 or linseed 

 oil, 156 respectively, was the dietary fat. Sinclair demonstrated that at 

 least one-third of the fatty acids in the liver of rats can be replaced by elaidic 

 acid when this acid or trielaidin is included in the diet, 93 and this substitu- 

 tion occurs within eighteen hours. On the other hand, elaidic acid is 

 taken up somewhat more slowly in the liver and other tissues of the cat. 157 



Rieckehoff and co-workers 158 reported that the polyunsaturated fatty 

 acid content of the tissues of rats was somewhat influenced by fat deficiency, 

 and by the feeding of fat diets, respectively. When rats on a fat-deficient 

 diet were given a single dose of the dienoic acid, linoleic acid, the amount 

 of arachidonic acid was found to be markedly increased in a number of 

 tissues. 158 ' 159 Linoleic acid could not serve as a source of hexaenoic 

 acids, 158 ' 159 except in the heart. 158 On the other hand, while the trienoic 

 acid, linolenic acid, was incapable of affording a source of the tetraenoic 

 acid, arachidonic acid, 159 it did give rise to pentaenoic and hexaenoic 

 acids. 159 The greatest deposition of polyunsaturated acids following the 

 feeding of a normal stock ration was shown to occur in the heart, followed 

 in decreasing order in the liver, brain, kidney, blood, and skeletal muscle. 159 

 Only negligible amounts were found in the adipose tissue. 



Although extreme deprivation of choline may lead to fatty livers, 

 choline-low diets may also result in differences in the lipid pattern, without 

 the development of fatty livers. A number of workers reported a signifi- 



162 E. M. MacKay and R. H. Barnes, Endocrinology, 22, 351-353 (1938). 



153 R. A. Shipley and E. G. Fry, Am. J. Physiol, 135, 460-463 (1942). 



154 G. Joannovics and E. P. Pick, Wien. klin. Wochschr., 23, 573-577 (1910). 



155 E. Shioji, J. Biochem. (Japan), 4, 43-72 (1924). 



166 K. Koizumi, J. Biochem. (Japan), 5, 171-185 (1925). 



167 R. G. Sinclair, J. Biol. Chem., 134, 71-81 (1940). 



158 I. G. Rieckehoff, R. T. Holman, and G. O. Burr, Arch. Biochem., 20, 331-340 

 (1949). 



159 C. Widmer, Jr., and R. T. Holman, Arch. Biochem., 25, 1-12 (1950). 



