420 VIII. CHOLESTEROL AND RELATED STEROLS 



Lumiere and Grange ^^^ noted that cholesterol, when administered in in- 

 jected serum, exerted a protective action against anaphylactic shock caused 

 by flocculation in the blood stream. 



a. Relation to Physiologically Important Compounds. Although the 

 physiologic relationship of cholesterol to the steroid hormones and to bile 

 salts had not been proved at the time when Bills'* wrote his review, it was 

 suggested that the physiologic relationship of cholesterol to other biologi- 

 cally important compounds which had a similar structure did present a 

 possibility of intriguing interest. Since 1953 it has been considered, on 

 the basis of various experiments, that cholesterol is the mother sub- 

 stance of the cholic acid residue of bile salts, and of sex hormones such as 

 pregnanediol,^-® the estrogens, and the androgens, and is related to the 

 adrenocortical hormones. It has been shown that 7-dehydrocholesterol, 

 which is an intermediate in the biosynthesis of vitamin D3, can originate 

 from cholesterol.^*^ It is therefore e\'ident that the cholesterol molecule 

 must be available if the biosynthesis of a number of physiologically im- 

 portant compounds is to proceed normally. 



On the other hand, according to Do\vnes,^^^ cholesterol is not an obliga- 

 tory intermediate in hormone synthesis. Since both steroid hormones 

 and cholesterol can be synthesized from acetate, there is probably at some 

 point a branching in the synthetic pathway, so that the molecules which 

 follow one path become cholesterol, and those which follow the other give 

 rise to the hormones. This does not rule out the possibility that transfor- 

 mation of the cholesterol is an alternative method of preparing hormone 

 molecules. ^^^ 



38* A. Lumiere and R. H. Grange, Compt. rend., 191, 423-425 (1930). 



3*5 H. R. Downes, The Chemistry of Living Cells, Harpers, New York, 1955. 



