LIPIDS PRESENT IN REPRODUCTIVE ORGANS 775 



Okey and her collaborators 389 compared the cyclic changes in the lipid 

 composition of the corpus luteum and of the uterine mucosa of the pig. 

 It was found that the total lipid content of the uterine mucosa (based upon 

 dry weight) was approximately the same as that of the lung, kidney, or 

 pancreas of beef. During the period of greatest elaboration of endo- 

 metrium, a small but definite increase in lecithin obtained, together with an 

 increase in free cholesterol. The lecithin : cholesterol ratios were conse- 

 quently lower than those existing simultaneously in the corpus luteum. 

 Moreover, a minimum amount of cholesterol ester was found in the endo- 

 metrium in all cases. 



(4) Lipids in the Placenta 



According to Watanabe, 390 the total lipids present in the placenta are 

 higher in early pregnancy than they are as term approaches. Phospholipid, 

 chiefly lecithin, was found to the extent of approximately 30%, while 

 neutral fat accounted for 27% of the total lipid. Cholesterol was likewise 

 present in both free and ester form. Cmelik 391 reported that the total fat 

 content of human placenta, obtained at term, was only 0.5% of the moist 

 weight. Slightly more than 50% of the fatty acids obtained from the pla- 

 centa lipid were water-soluble, which is a most unusual feature for any 

 tissue. It is suggested that higher fatty acids may be built up in the epi- 

 thelial cells and then excreted into the surrounding fluid. The water-in- 

 soluble acids consisted largely of unsaturated acids, although stearic acid 

 was also identified. Cholesterol accounted for 88% of the unsaponifiable 

 fraction. However, no squalene could be demonstrated chromatographi- 

 cally. This hydrocarbon had previously been shown to be a component in 

 ovarian dermoid cysts 392 and in the depot fat of women. 393 Cmelik and his 

 co-workers 394,395 likewise demonstrated the presence of squalene in the 

 vernix caseosa (waxy substance covering the fetus at birth). This com- 

 pound was absent from the lipids present in skin atheroma. 396 



389 R. Okey, W. R. Bloor, and G. W. Corner, /. Biol. Chem., 86, 307-314 (1930). 



390 H. Watanabe, /. Biochem. (Japan), 2, 369-397 (1923). 



391 S. Cmelik, Biochem. Z., 822, 150-153 (1951). 



392 A. Dimter, Z. physiol. Chem., 270, 247-265 (1941). 



393 E. Calandra and P. Cattaneo, Rev. Soc. argent. Biol, 24, 275-285 (1948); Chem. 

 Abst., 4$, 8494 (1949). 



394 S. Cmelik, N. Petrak-Longhino, and F. M. Mihelic, Biochem. Z., 822, 355-359 

 (1952). ^ 



395 S. Cmelik, N. Petrak-Longhino, and F. M. Mihelic, Arhiv. Kern. (Zagreb), 22, 236- 

 237 (1950); Chem. AbsL, 45, 10352 (1951). 



396 S. Cmelik, Biochem. Z., 822, 497-501 (1952). 



