362 VIII. CHOLESTEROL AND RELATED STEROLS 



proposed an empirical formula for cholesterol as early as 1888, the correct 

 structural formula was not finally discovered until the work of Rosenheim 

 and King,^"'' and especially that of Wieland and Dane,^ was completed in 

 1932. For a more complete exposition of the historical development of 

 our ideas on the chemistry and structure of cholesterol and of related 

 sterols, the reader is referred to The Lipids, Vol. I, pages 319 to 363. The 

 early development in the field of sterols, from the standpoint of both 

 chemistry and metabolism, was reviewed in 1935 by Bills. ^ The more 

 technical side of steroid chemistry has been summarized in the monograph 

 of Fieser and Fieser.^" Other reviews include those of Schoenheimer^^ on 

 sterol metabolism, the recent ones of Bloch,^--^^ a symposium published by 

 Gordon^^ in 1950, the reviews of Lieberman and Dobriner,'^ Samuels and 

 Reich, ^^ and Klyne,'^ and the most recent metabolic study of Staudinger 

 and Stoecki^ in 1954. 



2. The Absorption and Transport of Cholesterol and of Other 



Sterols 



Of the various natural sterols, cholesterol is most readily absorbed from 

 the gastrointestinal tract. The absorption of cholesterol may be demon- 

 strated by the increased level of blood, lymph, and tissue cholesterol after 

 this alcohol is fed. As early as 1906, Pribram^' reported a rise in the level 

 of blood cholesterol of rabbits after the administration of this compound as 

 the free alcohol or as its ester. Gardner and co-workers, -"""- among others, 



^ O. Rosenheim and H. King, Chemistry & Industry, 51, 464-466 (1932). 

 « O. Rosenheim and H. King, Nature, ISO, 315 (1932). 



7 O. Rosenheim and H. King, J. Soc. Chem. Ind., 52, 299-301 (1933). 



8 H. Wieland and E. Dane, Z. phijsiol. Chem., 210, 268-281 (1932). 



9 C. E. Bills, Physiol. Revs., 15, 1-97 (1935). 



1" L. F. Fieser and M. Fieser, Natural Products Related to Phenanthrene, 3rd ed., 

 Reinhold, New York, 1949. 



11 R. Schoenheimer, Science, 7Jf, 579-584 (1931). 



12 K. Bloch, Recent Progr. Hormone Research, 6, 111-129 (1951). 



13 K. Bloch, Harvey Lectures, 48, 68-88 (1952-1953). 



1'' E. S. Gordon, A Symposium on Steroid Hormones, Univ. Wisconsin Press, 1950. 



" S. Lieberman and K. Dobriner, Ann. Rev. Biochem., 20, 227-264 (1951). 



16 L. T. Samuels and H. Reich, Ann. Rev. Biochem., 21, 129-178 (1952). 



" W. Klyne, Synthesis and Metabolism of Adrenocortical Steroids, Ciba Foundation 

 CoUoquia on Endocrinology, Vol. VII, Little, Brown, Boston, 1953. 



18 H. Staudinger and G. Stoeck, Stoffwechsel des Cholesterins und der Steroidhormone, 

 in B. Flaschentrager and E. Lehnartz, Physiologische Chemie, lOth ed., 2, Part I. Der 

 Stoffwechsel, Sect, h, 869-908, Springer, Berlin, 1954. 



18 H. Pribram, Biochem. Z., 1, 413-424 (1906). 



2« C. Doree and J. A. Gardner, Proc. Roy. Soc. (London), B 81, 109-128 (1909). 



21 M. T. Eraser and J. A. Gardner, Proc. Roy. Soc. (London), B 81, 230-247 (1909). 



22 M. T. Fraser and J. A. Gardner, Proc. Roy. Soc. (London), B 82, 559-568 (1910). 



