EXCRETION OF LIPIDS BY WAY OF LARGE INTESTINE 347 



Sperry 599 reported that the non-saponifiable fraction in the fecal lipids of 

 dogs accounts for 35 to 40% of the total, while the fatty acids comprise 55 

 to 60%. The non-saponifiable fraction contains principally cholesterol, 

 coprosterol, and other sterols. Burger and Winterseel 103 reported that 

 about 50% of the sterol in human feces consisted of cholesterol, and 50% 

 of coprosterol; 10 to 30% of the sterols were in an esterified form. Ed- 

 wards and Cook 622 cited a value of 34% for the unsaponifiable content in 

 human feces. The proportion of cholesterol to coprostanol is increased 

 when cholesterol dissolved in oil is added to a mixed diet. 



The comparative distribution in normal feces as summarized by Cook 105 

 is given in Table 12. 



Much information as to the nature of fecal fat has been afforded by the 

 use of Thiry-Vella loops and by a number of other types of fistulas. Ange- 

 vine 624 reported that the lipid secretion from such Thiry-Vella fistulas in 

 dogs is extremely constant when based upon the amount per kilogram 

 body weight per day; no consistent variations were noted when a high- 

 fat or low-fat regimen replaced the normal diet. In an ingenious series of 

 tests, Sperry and Angevine 625 demonstrated a much greater secretion of 

 fat into the ileum than could be recovered from the isolated colon. On the 

 basis of these data, the hypothesis was formulated that considerable 

 amounts of the lipids secreted into the intestine are reabsorbed. 



624 R. W. Angevine, /. Biol. Chem., 82, 559-565 (1929). 



625 W. M. Sperry and R. W. Angevine, J. Biol. Chem., 96, 769-786 (1932). 



