LIPIDS PRESENT IN LIVER 713 



saponifiable extract in the case of beef liver. Cholesterol was shown to 

 comprise the largest proportion of the total sterols, although small amounts 

 of dihydrocholesterol and ergosterol were also present. According to 

 Chanutin and Ludewig, 48 free cholesterol comprises over 80% of the total 

 cholesterol in rat liver. 



The levels of liver cholesterol approximate 200 to 300 milligram per cent 

 of the wet weight of the organ (or 2 to 3 mg./g. liver) . This applies to the 

 figure reported by Bloor 49 for beef liver, which is 0.93% on the dry basis, or 

 2.8 mg./g. liver on the wet basis (assuming that the water content of normal 

 liver is 70%). In the case of normal rats, the figures per gram liver in- 

 clude 1.0 mg., 50 - 51 2.7 mg., 48 2.8 mg. (assuming that the water content of 

 normal liver is 70%), 52 and values ranging from 2.1 to 3.1 mg. 53 Similar 

 figures have been recorded for the cholesterol in the liver of chickens 

 (2.6 mg.), 54 of cats (5.05 mg.), 51 and of mice (2.2 mg.). 51 Free cholesterol 

 was also shown to constitute the major portion of the total in the livers of 

 chickens (93%) . 54 



(b) Hydrocarbons. Hydrocarbons may constitute a considerable por- 

 tion of the liver lipids, particularly in the case of certain fishes. Thus, 

 Tsujimoto 55 first reported the presence of an unsaturated hydrocarbon in 

 the liver oil of the black shark of the genus Zameus. This compound was 

 later shown to have an empirical formula of C30H50, and was named squal- 

 ene. 56 It has later been reported as present in the livers of sixteen of thirty- 

 six species of elasmobranch fishes from Japanese waters. 57 Klenk 58 also 

 demonstrated the presence of squalene in the liver oil of the dogfish, a 

 shark of the Squalidae (Etmopterus spinax). It comprises a large portion 

 of the 50% of the unsaponifiable fraction in this liver oil. 



Pristane, C18H38, is a somewhat similar hydrocarbon, which Tsujimoto 69 - 60 



48 A. Chanutin and S. Ludewig, J. Biol. Chem., 102, 57-65 (1933). 



49 W. R. Bloor, Biochemistry of the Fatty Acids, Reinhold, New York, 1943. 



50 D. Yuasa, Beitr. pathol. Anat. it. allgem. Pathol. (Zeigler's), 80, 570-594 (1928). 

 61 R. Schonheimer and D. Yuasa, Z. physiol. Chem., 180, 5-16 (1929). 



52 W. M. Sperry and V. A. Stoyanoff, J. Nutrition, 9, 131-155 (1935). 

 63 R. Alfin-Slater, M. C. Sehotz, S. M. Greenberg, and H. J. Deuel, Jr., unpublished 

 results, 1952. 



84 W. M. Sperry and V. A. Stoyanoff, /. Nutrition, 9, 157-161 (1935). 



56 M. Tsujimoto, J. Soc. Chem. Ind., Japan, 9, 953 (1906). Cited by M. Tsujimoto, 

 J. Ind. Eng. Chem., 8, 890 (1916). 



66 M. Tsujimoto, J. Ind. Eng. Chem., 8, 889-896 (1916). 



57 M. Tsujimoto, /. Ind. Eng. Chem., 12, 63-73 (1920). 



58 E. Klenk, Z. physiol. Chem., 217, 228-236 (1933). 



59 M. Tsujimoto, Bull. Chem. Soc. Japan, 10, 144-148, 149-153 (1935); /. Chem. 

 Soc. Japan, 55, 702-711 (1934); Chem. Abst., 28, 6484 (1934). 



60 M. Tsujimoto, ./. Ind. Eng. Chem., 9, 1098-1099 (1917). 



