PHYSIOLOGY OF ADIPOSE TISSUE 615 



Baker and associates. 451 These workers demonstrated that an increase in 

 the glyceride content of brown adipose tissue resulted when intact or cas- 

 trated rats were injected with ACTH (adrenocorticotropic hormone). 

 However, the pituitary gland, also, appears to be necessary to produce this 

 effect; following the injection of even as much as three times the effective 

 dose of ACTH, it was impossible to maintain the normal fat content of the 

 interscapular gland of hypophysectomized rats. 451 



Another explanation for the fat deficit in animals following adrenalec- 

 tomy is the failure to synthesize fats from glycogen in the adipose tissue 

 under these conditions. 120 Only negligible amounts of glycogen are stored 

 in the fat depots of animals after removal of the adrenals, whereas normally 

 the tissues would be heavily charged with this polysaccharide. However, 

 glycogen deposition could be brought about either by the administration of 

 pure desoxycorticosterone acetate or by cortical extracts. It is therefore 

 suggested that the basic reason for the decreased fat storage following ad- 

 renalectomy is the fact that the carbohydrate -*- fat change does not occur 

 normally in the absence of the cortical hormones. Consequently, the fat 

 depots fail to become filled. 



Another suggestion which has been advanced to account for the absence 

 of fatty livers in the adrenalectomized animals is that this organ cannot 

 retain fat, or that it has a higher rate of fat metabolism than the normal. 

 It has been found that, following fat ingestion, animals without adrenals 

 store less fat in their livers than do normal controls. 446 These results all 

 add up to the conclusion that fat storage in both the liver and the fat depots 

 is inhibited after extirpation of the adrenal glands. 



There also appears to be some indication that the hormone of the medul- 

 lary portion of the adrenal gland, namely epinephrine, may have some effect 

 on fat mobilization. Clement and Schaeffer 452 have demonstrated that 

 epinephrine possesses this action. It is postulated that the effect of the 

 pituitary hormones might be due to the adrenotropic hormone. However, 

 if this is the case, the influence would be an indirect one, which is exerted 

 through the nervous system. 



c'. The Regulation by Insulin: Wertheimer 453 was the first to demon- 

 strate that insulin is able to counteract the fatty livers which develop in 

 animals having phlorhizin diabetes. This hormone also partially prevents 

 the production of fatty livers resulting from the injection of anterior pitui- 



151 B. L. Baker, D. J. Ingle, and C. H. Li, Proc. Soc. Exptl. Biol. Med., 73, 337-339 

 (1950). 



482 G. ("lenient and G. Schaeffer, Compt. rend. soc. biol., 141, 320-322 (1947). 

 453 E. Wertheimer, Arch. ges. Physiol. (Pfliiger's), 213, 298-320 (1926). 



