J 08 II. DIGESTION AND ABSORPTION OF FATS 



in the intestinal mucosa. Bloom et al., m using C "-labeled palmitic acid, 

 also showed that, during the absorption of fat, the intestinal lymph con- 

 tributes phospholipid to the plasma. It was believed that these phos- 

 pholipids were synthesized in the small intestine. Borgstrom 788 noted that 

 the neutral fat comprised 90% and phospholipids 10% of the total lipids, 

 irrespective of whether the fats were fed as triglycerides or as free fatty 

 acids. No free fatty acids or soaps occurred in the lymph. Little change 

 in the cholesterol, as a result of fat feeding, was observed in lymph obtained 

 from any of these sources. 781 



The proportion of ingested fatty acids which is transported by the lymph 

 has been shown to vary with the fatty acid component of the triglyceride. 

 Thus, Bloom et al. 777 found that practically all of the palmitic acid adminis- 

 tered as triglyceride to rats could be accounted for in the thoracic lymph. 

 Chaikoff et al 7S9 reported similar findings for pentadecanoic acid. In a 

 later study, 790 it was reported that C 14 -labeled stearic and myristic acid 

 could also be recovered practically quantitatively in the lymph. It is 

 concluded that the lymph is the major if not the exclusive pathway for the 

 absorption of fats containing long-chain acids. When similar experiments 

 were carried out with lauric and decanoic acids, the recovery in the lymph 

 was only 15-55% and 5-19%, respectively. This is interpreted as evi- 

 dence of the transport of these acids via the portal route (see following sec- 

 tion). 



b. The Transport of Fat in the Portal Circulation. In spite of the fact 

 that the bulk of the fat is carried from the intestine in the lymph, one must 

 still accept the possibility that a portion of it travels by way of the portal 

 circulation. Numerous investigators 79 1 ~ 796 have shown an increase in the 

 fat of the portal blood during fat absorption. Cantoni 795 reported that 

 portal blood contained more fatty acids than did arterial blood, and Eck- 



787 B. Bloom, I. L. Chaikoff, W. O. Reinhardt, and W. G. Dauben, J. Biol. Chem., 189, 

 261-267 (1951). 



788 B. Borgstrom, Acta Chem. Scand., 5, 643-646 (1951). 



789 1. L. Chaikoff, B. Bloom, B. P. Stevens, W. O. Reinhardt, and W. G. Dauben, J. 

 Biol. Chem., 190, 431-435 (1951). 



790 B. Bloom, I. L. Chaikoff, and W. O. Reinhardt, Am. J. Physiol., 166, 451-455 

 (1951). 



791 G. D'Errico, Arch, fisiol., 4, 513-522 (1907). 



792 H. Roger and L. Binet, Compt. rend. soc. bid., 86, 79-80 (1922). 



793 W. W. L. Glenn, S. L. Cresson, F. X. Bauer, F. Goldstein, O. Hoffman, and J. E. 

 Healy, Jr., Surg. Gynecol. ObsteL, 89, 200-208 (1949). 



79 « J. A. Sicard, R. Fabre, and G. Forestier, Bull. soc. chim. biol, 5, 413-425 (1923). 



796 O. Cantoni, Boll. soc. ital. biol. sper., 8, 1278-1282 (1928). 



796 S. W. Nedswedski, Arch. ges. Physiol. (Pfluger's), 214, 337-342 (1926). 



