INTERMEDIARY METABOLISM OF CHOLESTEROL 409 



Somewhat similar results were recorded by Anselmino and Hoffmarm^^^ 

 and by Saegesser.^^^ The conclusions were Hkewise confirmed independ- 

 ently on a different strain of rats, by Ershoff and Marx.^^^ 



The reason for the protective effect of the added cholesterol is problem- 

 atical. One suggestions^" is that cholesterol protects the body from prod- 

 ucts resulting when a breakdown of lecithin to lysolecithin occurs, a reaction- 

 which Hoffmann and de Hoffmann ^^^ believe is stimulated by the thyroid 

 hormone. Since lysolecithin is supposed to affect the central nervous sys- 

 tem, to influence cell permeability, and to exert "toxic effects in various 

 organs" at high concentrations, ^^^ any substance, such as cholesterol, 

 which counteracts or neutralizes lysolecithins would have a protective ac- 

 tion. Another possible explanation is that the concentration of choles- 

 terol in key sites, as, for example, in the adrenocortical tissues, is reduced to 

 a subnormal level, in the group not receiving cholesterol, by the constant 

 stimulation of the thyroid hormone. The synthesis of adrenocortical hor- 

 mones from cholesterol is decreased to such an extent that the animals die 

 as a result of the deficiency of these hormones. When cholesterol is ad- 

 ministered, the quantity of the sterol is maintained at a sufficiently high 

 level in the various tissues (including the adrenal cortex) to insure an ade- 

 quate amount of precursors of adrenocortical hormones at all times. 



(6) Conversion to Androgens 



According to Niwelinski,^^^ cholesterol also acts as a precursor of andro- 

 gens. Thus, it will cause a stimulation of spermatogenesis and the secre- 

 tion of ketosteroid hormones when it is implanted in the testes. However, 

 the atrophy of the testes induced by deficiency of vitamin Bi persists in 

 spite of cholesterol administration, whereas the administration of sex hor- 

 mones corrects the condition. It is possible that vitamin Bi is required 

 for the transformation of cholesterol into androgens. Brady^^'' demon- 

 strated the in vitro synthesis of one of the androgens, testosterone, by sur- 

 viving slices of testicular tissue from the hog, rabbit, and human testes; 

 however, in this case the synthesis involved acetate, and evidence is pre- 



"1 K. J. Anselmino and F. Hoffmann, Klin. Wochschr., 12, 99-102 (1933). 



"2 M. Saegesser, Klin. Wochschr., 12, 672 (1933). 



S33 B. H. Ershoff and W. Marx, Ex-ptl. Med. Surg., 6, 145-148 (1948). 



"■• F. Hoffmann and E. J. de Hoffmann, Piibl. Inst, fisiol., Univ. Chile, 1943; cited 

 bv F. F. Foldes and A. J. Murphy, Proc. Soc. Exptl. Biol. Med., 62, 218-223 (1946), p. 

 220, and bv B. H. Ershoff and W. Marx, Exptl. Med. Surg., 6, 145-148 (1948), p. 147. 



335 Y. F.'Foldes and A. J. Murphy, Proc. Soc. Biol. Med., 62, 218-223 (1946). 



336 J. Niwelinski, Compt. rend. soc. bioL, 146, 1030-1033 (1952). 

 3" R. O. Brady, /. Biol. Chem., 193, 145-148 (1951). 



