112 II. DIGESTION AND ABSORPTION OF FATS 



itself, where it is assumed that the}' may act continuously as transporters 

 of fat. However, these bile acids are gradually carried to the liver by way 

 of the portal blood supply, rather than by the lymphatic route. In support 

 of this hypothesis, Josephson and Rydin 564 have shown that a higher level 

 of cholate occurs in the portal blood than in the systemic blood of rabbits 

 and cats (2.5 to 5 mg./lOO ml. in portal blood compared with 1 to 2 mg./lOO 

 ml. in blood from the heart). The discrepancy between the content of bile 

 acids in the portal and in the systemic blood is increased when bile salts are 

 introduced into the intestine, 565 while no difference obtains when there is no 

 bile in the intestine, due to previous ligation of the bile duct. 564 Similar 

 results were obtained on dogs by Josephson and Kaunitz; 566 in normal dogs, 

 the lymph never contained cholates in concentrations high enough to be 

 determined, even when a considerable absorption of bile salts was taking 

 place. On the other hand, the cholate concentration in the portal blood 

 was markedly augmented during the absorption of bile. Jenke and Graff 567 

 reported similar results. The absorption of the bile is believed to take 

 place chiefly in the ileum, although sodium glycocholate can be absorbed 

 in the jejunum. The absorption of bile salts in the duodenum is zero, 568 or 

 at least minimal. 569 



The absorption of bile acids from the intestine was demonstrated by 

 Johnston and Irvin 570 in patients with choledochostomy drainage over 

 periods of 10 to 20 postoperative days, before the resumption of synthesis 

 of bile acids had occurred. During this period, a considerable fraction of 

 the acids was unconjugated; the excretion of the dihydroxycholanic acids 

 occurred before that of cholic acid. 



When desiccated hog bile was given orally, not only was an excretion of 

 hyodesoxycholic acid observed in the drainage bile, but also the ratio of 

 bile acids conjugated with glycine to those combined with taurine increased. 

 It was suggested that glycohyodesoxycholic acid was absorbed and re- 

 excreted unchanged in the drainage bile. When ox bile was administered, 

 the cholic and desoxy cholic acids in the drainage bile were increased in 

 proportion to the amount of these acids present in the ox bile. These re- 



664 B. Josephson and A. Rydin, Biochem. J., 30, 2224-2228 (1936). 



S6B C. H. Greene, M. Aldrich, and L. G. Rowntree, /. Biol. Chem., 80, 753-760 (1928). 



566 B. Josephson and H. Kaunitz, Z. ges. exptl. Med., 102, 195-201 (1937). 



56 ' M. Jenke and U. Graff, Klin. Wochschr., 18, 125-127 (1939). 



568 H. Tappeiner, Sitz-Ber. Akad. Wiss., Wien, Math.-Naturw. Klasse, 77, Abt. II. 

 281-304 (1878). 



569 E. Frolicher, Biochem. Z., 283, 273-279 (1935-1936). 



570 C. G. Johnston and J. L. Irvin, J. Clin. Invest., 26, 802-814 (1947). 



