LIPID CONTENT AND COMPOSITION OF ANIMAL 583 



a control is exerted by the female sex hormones over carbohydrate metab- 

 olism. The sex difference in liver glycogen in normal rats is shown by 

 markedly higher values for males than for females, except in immature and 

 old rats, in which cases the figures are the same. 275 Blatherwick and asso- 

 ciates 276 likewise confirmed the sex differences in liver glycogen values in 

 this species. 



Further evidence of sex variation in the composition of the liver lipids is 

 to be found in later work of Deuel et al. 277 ; in these experiments, fatty livers 

 were produced by dietary means. A sex difference in glycogen content was 

 consistently observed in the livers of unfasted rats fed choline-free diets con- 

 taining different fats, in that higher levels were observed in the male rats 

 as compared with the females. Furthermore, the liver lipids were usually 

 found to be considerably higher in the female rats than in the males. 277 

 Similar variations in liver lipids have been recorded by Best et al. 278 Shor- 

 land 279 recorded higher values for lipids in the livers of the female New 

 Zealand grouper (Polijprion oxygeneios) than in the male fish, although the 

 differences were not statistically significant. 



Several workers have noted that different lipids have separate sex pat- 

 terns. Thus, Okey and co-workers 280 reported that, in spite of the fact that 

 the total lipid in the livers of female rats was consistently higher than in 

 male animals, total cholesterol was higher in the males. This occurred 

 both on a normal diet in which the cholesterol levels were 1.2 and 1.0 milli- 

 gram per cent respectively, for the livers of males and of females, and on a 

 regimen containing 1% of cholesterol, in which the liver cholesterol figures 

 were 15.2 and 11.7 milligram per cent, respectively. Likewise, the lecithin 

 values were slightly higher in the livers of male rats than in females. Obvi- 

 ously, the neutral fat fraction must be considerably higher in the female 

 than in the male to account for the higher total lipid content in the former 

 case. The results obtained by Okey et al. 2 * have been confirmed by Barnes, 

 Miller, and Burr, 281 who noted that the higher lipid value in the females 

 as compared with the males was confined to the acetone-soluble fraction 

 (neutral fat), while it was not observed in the phospholipid fraction. 



275 H. J. Deuel, Jr., J. S. Butts, L. F. Hallman, S. Murray, and H. Blunden, /. Biol. 

 Chem., 119, 617-620 (1937). 



276 N. R. Blatherwick, P. J. Bradshaw, O. S. Cullimore, M. E. Ewing, H. W. Larson, 

 and S. D. Sawyer, /. Biol. Chem., 113, 405-410 (1936). 



277 H. J. Deuel, Jr., L. F. Hallman, and S. Murray, J. Biol. Chem., 119, 257-268 

 (1937). 



278 C. H. Best, J. H. Ridout, J. M. Patterson, and C. C. Lucas, Biochem. J., 48, 448- 

 452(1951). 



279 F. B. Shorland, unpublished observations, 1953. 



280 R. Okey, H. L. Gillum, and E. Yokela, J. Biol. Chem., 107, 207-212 (1934). 



281 R. H. Barnes, E. S. Miller, and G. O. Burr, J. Biol. Chem., 140, 247-253 (1941). 



