DIGESTION, ETC. OF STEROLS IN THE G.I. TRACT 267 



line cholesterol was added to a diet containing 50 g. of olive oil, while a 

 figure of 60% (equivalent to 6.9 g. of cholesterol) was found when chole- 

 sterol was given as egg yolk along with 360 g. of fat. m 



In studies on man, in which the criterion of absorption is an elevation 

 in plasma cholesterol, rather than fecal excretion, transient increases in 

 plasma cholesterol have been noted after the ingestion of large amounts 

 of cholesterol in the form of eggs. 106,107 On the other hand, Gough 108 was 

 unable to demonstrate any appreciable increase of cholesterol, either in the 

 plasma or in the bile, when this sterol was fed as the crystalline compound 

 or as sheep brain, in the amount of 2 g. cholesterol in 50 g. brain. In 

 his review of comparative aspects of lipid absorption and excretion, 

 Cook 106 states that the absorption of cholesterol in man is not marked, 

 and that the level is kept fairly constant; the ingestion of fat alone, 

 however, may result in a hypercholesterolemia. 



(b) Balance Experiments on Animals. Cook and Thomson 109 reported 

 that the maximum amount of cholesterol which can be absorbed per 

 kilogram of body weight is fairly uniform in the rat, guinea pig, and rabbit. 

 However, the coefficient of digestibility was found to be highest in the 

 rabbit, lower in the guinea pig, and lowest in the rat. Had the chole- 

 sterol been fed at a standard dosage per kilogram body weight, it is prob- 

 able that the coefficients of digestibility obtained might have been more 



Table 5 

 The Comparative Cholesterol Absorption in Different Animals" 



Guinea 

 Category Rat pig Rabbit 



Cholesterol 



Fed, g./kg. body wt./day 1.05 0.55 0.37 



Absorbed, g./kg. body wt./day 0.35 0.25 0.25 



Absorption, % 34 47 77 



Plasma cholesterol, mg./lOO ml. 



Control 70 95 148 



After cholesterol feeding 222 271 1720 



» Adapted from R. P. Cook and R. O. Thomson, Quart. J. Exptl. Physiol, 36, 61-74 

 (1951). 



105 R. P. Cook, "Comparative Aspects of Lipid Absorption and Excretion," in R. T. 

 Williams, Lipid Metabolism, Biochem. Soc. Symposia, No. 9, 14-29, Cambridge Univ. 

 Press, 1952. 



106 R. Okey and D. Stewart, ./. Biol. Chem., 99, 111-121 (1933). 



107 M. F. Collen, D. de Kruif, and F. Geier, Permanmte Foundation (Oakland, Calif.) 

 Med. Bull, 7, 60-60(1949). 



108 N. Gough, Brit. Med. ./., 1943, II, 390-391. 



109 R, P. Cook and R. O. Thomson, Quart. J. Exptl. Physiol, 36, 61-74 (1951). 



