LIPID CONTENT AND COMPOSITION OF ANIMAL 585 



Table 13 



The Effect of Ovariectomy and of Thyroxine Feeding on the 



Distribution and Quantity of Fat in Female Rats° 



Series II 



Series I 



Thyroxine-fed rats 



Normal Ovari- Normal 



female ectomized female Started Started 



Category rats rats rats at 100 g. at 200 g. 



Number of rats 5 7 4 4 4 



Final body weight, g 216 252 222 188 235 



Proportion of total depot fat, % 



Intermuscular 8.8 8.7 8.7 6.6 8.9 



Genital 22.4 12.9 22.0 23.2 21.5 



Subcutaneous 44.3 56.0 44.9 43.7 42.2 



Perirenal 13.5 13.0 14.8 16.0 15.9 



Mesenteric 7.9 6.6 5.6 7.7 8.8 



Omental 3.2 2.5 2.5 3.1 2.7 



Depot fat, % body wt 12.6 14.2 13.8 6.3 6.4 



a Adapted from L. L. Reed, W. E. Anderson, and L. B. Mendel, ./. Biol. Chem., 96, 

 313-323 (1932). 



Although the effect of ovariectomy in increasing the total body fat is not 

 very marked in the rat, there can be no doubt that the operation results in a 

 marked redistribution of fat. Reed et al. m found no change in the char- 

 acter of the fat following ovariectomy, since the iodine numbers of the fat 

 of the experimental and of the control animals were practically identical. 

 Apparently obeshVy results from gonadectomy to a greater extent in fowls 

 than in the rat. According to Korenchevsky 289 "birds develop obesity so 

 regularly after the removal of the sexual glands that this operation is em- 

 ployed commercially for fattening animals for food." 



(e) Sex Differences in Fat Metabolism. In addition to variations in the 

 total amount and the distribution of lipids, as related to sex, there is con- 

 siderable evidence that a sex difference obtains in the metabolism of this 

 foodstuff. The metabolic difference may be related to the variations in fat 

 storage. A more intense fat oxidation can be demonstrated in the female 

 than in the male, during fasting. This accelerated rate of fat breakdown 

 is indicated by the markedly higher degree of ketonuria which occurs in 

 fasting women as contrasted with fasting men. Deuel and Gulick 290 re- 

 ported that the average ketone body excretion during fasting, based upon 

 surface area, is approximately five times as great in the case of women as in 

 men. A similar sex difference in ketonuria has likewise been demonstrated 

 in the exogenous ketonuria produced when acetoacetic (diacetic) acid, bu- 



289 V. Korenchevsky, Brit. J. Exptl. Pathol, 6, 21-35 (1925). 



290 H. J. Deuel, Jr., and M. Gulick, J. Biol. Chem., 96, 25-34 (1932). 



