358 



On the Origin and Destiny of Cholesterol in the Animal Organism. 

 Part XII. — On the Excretion of Sterols in Man. 



By John Addyman Gardner and Francis William Fox (Beit Memorial 



Fellow). 



(Communicated by Prof. A. D. Waller, F.R.S. Received July 11, 1921.) 



(Report to the Medical Research Committee. From the Physiological Laboratory, 

 University of London, South Kensington.) 



In Part X of this series [vol. 86, p. 13 (1912)]— " On the Excretion of 

 Cholesterol by Man " — Ellis and Gardner, from analyses of the dried faeces 

 collected during a series of experiments, carried out by E. H. A. Plimmer, 

 M. Dick, and E. C. lieb, at the Institute of Physiology, University College, 

 and published, under the title of " A Metabolism Experiment, with Special 

 Reference to Uric Acid," came to the conclusion that in man the excretion of 

 cholesterol in the faeces can be largely accounted for by that taken in with 

 the food, provided that the body weight remains constant ; if, however, a 

 rapid loss in weight takes place, as in illness, the output of sterol exceeds the 

 intake. 



Further work has shown that this conclusion requires modification. In 

 the above-mentioned investigation only one subject was experimented on and 

 the cholesterol-content of the diet was not obtained by analysis of samples of 

 the food actually consumed by the subject under experiment, since the 

 examination of the fseces in question was not undertaken until long after the 

 completion of Plimmer, Dick, and Lieb's investigation, and was of the nature 

 of an afterthought. 



The cholesterol ingested was estimated, partly from analyses of similar 

 foods purchased long afterwards, and partly from published analyses of other 

 observers. Further, in the examination of the faeces it was assumed that the 

 only sterol present in the unsaponifiable matter was the crystalline coprosterol. 

 This was separated from the accompanying oils, as far as possible, by crystalli- 

 sation from alcohol or acetone. The last traces remaining in solution were 

 obtained by conversion into the benzoate, which is only soluble with 

 difficultly in cold alcohol. This method necessitates the use of large 

 quantities of material to obtain accurate results. 



Since the publication of this work, new and improved methods for the 

 estimation of sterols in tissues, etc., have been introduced, and, further, our 

 knowledge of the composition of the unsaponifiable matter of human faeces 

 has been considerably extended. 



