ROLE OF BILE IN LIPID ABSORPTION 1 13 



suits furnish cogent support for the absorption and reexcretion of the bile 

 salts. 



(b) Reexcretion of the Bile Acids. Whipple and Smith 571 ' 572 confirmed the 

 earlier work of Tschernoff, 562 Stadelmann, 563 and Greene et a/. 565 by demon- 

 strating the marked effect of removal of the bile salts from the gastrointes- 

 tinal tract on the excretion of these acids in the bile. Dogs with bile fistu- 

 las were shown to produce only 100 mg. of bile salts per kilogram body 

 weight per day when they were deprived of their bile. This figure has also 

 been reported by Magee et al. for cholate 573 ; the latter workers suggest that 

 a reduced secretion of cholate is indicative of liver dysfunction, and that a 

 significant correlation exists between the mean deficit and the bromsulph- 

 thalein retention. On the other hand, when the excreted bile salts were 

 fed back to the dogs, the daily production of these components rose to 800 

 mg./kg./day. It was calculated that a 10 kg. dog keeps about 7 to 8 g. 

 of bile salts in circulation by resorption and by reexcretion, and that the 

 time required for the circulation of this amount is 8 to 16 hours. These 

 results are in line with those obtained by Schmidt and collaborators. 574 

 The bile salt secretion can be stepped up to 15 to 17 g. per day if the animal 

 is fed more bile salts than have been excreted. When higher amounts than 

 this quantity are given, the surplus is lost. 



There is some question as to the extent of the loss of bile salts in the course 

 of their recirculation through the fiver. Schmidt et a/. 574 estimated that, 

 when bile is given orally in physiological amounts, about 10% is lost. 

 Irvin and associates 559 reported that, during ten hours of circulation of 

 foreign conjugated bile salts in the hog, 10% of the amount circulated was 

 lost; on the other hand, unconjugated cholate was handled less efficiently. 

 It was also shown that the disappearance of hyodesoxycholic acid was com- 

 parable to the loss of the conjugated bile acids. The average equilibrium 

 level was 600 mg./kg., and this total amount was found to be unchanged 

 by the administration of cholate. In fact, no evidence for the conversion 

 of cholic acid to the dihydroxycholanic acids such as hyodesoxycholic 

 acid was demonstrated. Moreover, cholates did not appear in the pe- 

 ripheral circulation of normal hogs. However, when the bile flow was 

 obstructed, and cholates were administered either by the duodenal or the 



671 G. H. Whipple and H. P. Smith, J. Biol. Chem., 80, 697-707 (1928). 



472 G. H. Whipple and H. P. Smith, J. Biol. Chem., 89, 727-738 (1930). 



673 D. F. Magee, K. S. Kim, V. C. Pessoa, and A. C. Ivy, Am. J. Physiol, 169, 309-316 

 (1952). 



574 C. R. Schmidt, J. M. Beazell, A. L. Berman, A. C. Ivy, and A. J. Atkinson, Am. J. 

 Physiol, 126, 120-135 (1939). 



