ABSORPTION AND TRANSPORT OF FATS 159 



According to Fries et al., 7bl who employed phosphate containing P 32 , the 

 intestine is the most active gastrointestinal site for phosphorylation. In 

 the bird, a greater deposition of P 32 likewise occurs in the intestinal cells 7fin 

 than in the gizzard, proventriculus, cecum, or colon. After the oral ad- 

 ministration of phosphate-containing P 32 , Artom and co-workers 749 found 

 that the specific activity of phospholipid phosphorus in the intestine ex- 

 ceeded that in the liver. Recovery of P 32 was found to be greater in the 

 small intestine when the phosphate was given by stomach tube than when 

 it was administered subcutaneously. 751 The feeding of fat has been shown 

 to increase the deposition of phospholipid in the intestine. 749 Hevesy and 

 Hahn 748 reported that P 32 was incorporated in the cephalin molecule to the 

 largest degree at short intervals after the administration of the P 32 ; how- 

 ever, Chargaff 7f>2 has shown that lecithin contains a larger proportion of the 

 radioactive phosphorus after twenty-four hours than does cephalin. 



Another experimental procedure which has been employed to prove the 

 synthesis of phospholipid in the intestinal wall is the feeding of fats con- 

 taining fatty acids which can be identified. Thus, Artom and Peretti 711 

 were able to demonstrate that intestinal phospholipid contained iodized 

 fatty acids after iodized fats had been fed to rats; Sinclair and Smith 712 

 noted that fatty acids in the intestinal phospholipids of cats contained as 

 much as 35% of elaidic acid after trielaidin had been fed. Collet and 

 Favarger 756 reported that, when labeled elaidic acid, palmitic acid, or tri- 

 palmitin was fed to monkeys, a significant proportion of the fatty acids were 

 incorporated into the phospholipid of the intestinal mucosa; on the other 

 hand, very little of the tagged glycerol fed was found to become incor- 

 porated into the intestinal phospholipid. 



According to the Bloor hypothesis, as soon as the fatty acids are absorbed 

 in the epithelial cells, molecules of phospholipid react with them to form 

 triglycerides and a residual phosphoric acid -f- base complex. The latter 

 combines with new fatty acids and glycerol to form new phospholipid which, 

 in turn, passes through the same cycle with a new supply of fatty acids. 

 This hypothesis is based upon the experiments of Sinclair 703 who reported 

 that, although the total amount of phospholipid in the intestine did not 

 change during fat absorption, the fatty acids combined in the phospholipid 

 did change in response to the fatty acids which were being absorbed. How- 



752 E. Chargaff, J. Biol. Chem., 128, 587-595 (1939). 



753 R. G. Sinclair, J. Biol. Chem., 115, 211-220 (1936). 



754 L. Hahn and G. Hevesv, Compl. rend. trav. lab. Carlsberg, Sir. chim., 22, 188-192 

 (1938). 



755 G. Hevesy, Enzymologia, 5, 138-157 (1938). 



766 R. A. Collet and P. Favarger, Helv. Physiol, et Pharamcol. Acta, 9, C61-C62 (1951 ). 



