340 IV. DIGESTION OF LIPIDS OTHER THAN FATS 



The cholesterol in hepatic bile has been shown to be low when a severe 

 liver injury is present, although the situation is reversed when the liver 

 damage is slight. 593 Bile ordinarily contains only unesterified (free) 

 cholesterol, 67 - 594 - 595 although esterified cholesterol to the extent of 29% 

 of the total has been reported from one sample of gall-bladder bile. 594 



After cottonseed oil was given to a patient, a marked increase in bile 

 salts was noted, while the fatty acids and fats were only slightly aug- 

 mented. 596 The administration of glucose caused no change in bile lipids, 

 whereas peptone had only a slight effect in causing an elevation of the bile 

 lipids. 



b. Bile as a Source of Intestinal Lipids. Sperry 597 made an exhaustive 

 study of the role of the bile as the source of fecal lipids. In order to de- 

 termine this point, he carried out tests on bile-fistula dogs over a period of 

 five weeks. Although considerable variations in the lipid excretion occurred 

 during the course of the tests, no tendency toward a diminution in amount 

 was observed. The lipid excretion continued at levels 1.5 to 4.5 times the 

 normal. The fecal excretion was quite constant. The non-saponifiable 

 fraction comprised 31.4%, and the fatty acids 63.1% (41.9% liquid and 

 45.5% solid acids). It was concluded that bile is not the source of fecal 

 lipids. The results of Sperry 597 were confirmed by Beumer and Hepner. 598 



(2) The Excretion of Lipids by the Intestinal Wall 



It is now recognized that a considerable proportion of the lipid ex- 

 creted in the feces is secreted into the intestine below the level at which it 

 can be reabsorbed. Sperry 599 reported the presence, in the feces of dogs, 

 of usable free fatty acids not bound to cholesterol; this would indicate 

 that these acids are excreted through the intestinal wall rather than intro- 

 duced by way of the bile. Since the composition of the fecal fatty acids 

 resembles that of the plasma lipid, it is suggested that the acids represent 

 a leakage which has as its purpose the lubrication of the intestine. This 

 worker also suggests the possibility that the lipid excretion may be con- 

 cerned with the removal of undesirable excess sterols from the organism. 

 Peretti 600 demonstrated the secretion of fat by the intestinal mucosa in an 



694 C. Riegel, I. S. Bavdin, and H. J. Rose, Proc. Soc. Exptl. Biol. Med., 35, 94-97 

 (1936). 



595 W Wright, J. Exptl. Med., 59, 407-410 (1934). 



696 C. W. McClure, M. E. Huntsinger, and A. T. Fernald, Am. J. Physiol., 107, 1-12 

 (1934). 



597 W. M. Sperry, J. Biol. Chem., 71, 351-378 (1926-1927). 



598 H. Beumer and F. Hepner, Z. ges. exptl. Med., 64, 787-797 (1929). 



599 W. M. Sperrv, J. Biol. Chem., 68, 357-383 (1926). 

 «°° G. Peretti, Boll. soc. ital. biol. sper., 10, 79-80 (1934). 



