LIPID CONTENT AND COMPOSITION OF ANIMAL 593 



ranged from 5 to 50% of the lean body mass. On the other hand, the fat 

 content of heart, kidney, gut, muscle, bone, skin, and adipose tissue was 

 directly proportional to total body fat. The skin was found to be the most 

 sensitive to changes in total body fat. 



Moreover, the type of fat laid down in the different fat depots is usually 

 quite uniform, irrespective of diet. Only the omental fat consistently 

 shows some variation, in that it is slightly more saturated than the other 

 samples. The average iodine numbers of the fats from different storage 

 sites are given in Table 16. 



Table 16 

 The Iodine Numbers of Storage Fats from Various Sites as Affected by Diet" 



Starch Soybean oil Coconut oil 



Fat source diet diet diet 



Intermuscular 55.8 109.3 31.3 



Genital 54.3 113.4 29.2 



Subcutaneous 56.3 114.1 31.4 



Perirenal 53.7 113.9 29.9 



Mesenteric 51.4 110.5 29.1 



Omental 51.6 105.2 27.8 



° L. L. Reed, F. Yamaguchi, W. E. Anderson, and L. B. Mendel, /. Biol. Chem., 87, 

 147-174 (1930). 



g. The Effect of Inanition on the Content and Composition of Body Fat. 



When animals are fasted, a sparing action appears to be exerted on the 

 fatty acids which are specialized in their behavior, and above all on those 

 which are essentia,!. On the other hand, short-chain fatty acids, which 

 have been deposited in the fat depots by feeding a coconut oil diet, are most 

 rapidly utilized. All of these phenomena may result in a considerable 

 modification of the fatty acid distribution, as compared with the normal, 

 as inanition progresses. 



In the experiments of Hilditch and Pedelty, 336 which were carried out on 

 pigs after a previously normal diet, little variation was to be found in the 

 composition of the fat, even after 135 days of fasting, except for a decrease 

 in the oleic acid, with a small concomitant increase in stearic acid. The 

 linoleic acid, however, remained practically constant. The data for this 

 experiment are summarized in Table 17. 



Hilditch and Pedelty, 337 in a later communication, showed that, when fat 

 ewes were fasted for periods up to 209 days, a reduction of the palmitic acid 

 occurred in the storage depot, together with a slight increase in stearic acid. 



336 T. P. Hilditch and W. H. Pedelty, Biochem. J., 34, 40-47 (1940). 



337 T. P. Hilditch and W. H. Pedelty, Biochem.. J., 35, 932-939 (1941). 



