618 VI. OCCURRENCE OF LIPIDS IN THE ANIMAL 



pose tissue is necessary if this tissue is to maintain its dynamic equilibrium. 

 The maintenance of a "tonus" in adipose tissues is dependent upon con- 

 stant innervation; it may be changed by pathological conditions. Nerve 

 section is ordinarily followed by a deposition of fat in the tissue involved. 

 It is believed that the status of an animal as regards obesity or leanness, as 

 well as the localized deposition of fat, is related to the extent to which it is 

 subject to nervous stimuli. 



(4) Glycogen Deposition in Adipose Tissue 



It is only in recent years that the possibility of the presence of glycogen 

 in adipose tissue has been recognized. As early as 1906, Gierke 467 - 468 noted 

 glycogen in histologic preparations of adipose tissue. Other authors, how- 

 ever, were unable to demonstrate, by chemical tests, the presence of glyco- 

 gen in the fatty tissues of healthy dogs and rats, under normal conditions. 120 



On the other hand, Wertheimer et aZ. 120,469,470 reported that glycogen 

 could be demonstrated chemically in adipose tissues if the animals were 

 undernourished or fasted, and were then placed for a short time on a high 

 carbohydrate diet. However, the glycogen deposition was shown to be 

 transient, and it could no longer be demonstrated after carbohydrate feed- 

 ing had been continued for some time. The same conditions which aug- 

 ment fat storage in adipose tissues were found to enhance glycogen deposi- 

 tion ; the fact that the deposition of glycogen precedes fat deposition, and 

 that it ceases when fat is no longer laid down in increasing amounts, is evi- 

 dence that these two phenomena are directly interconnected. 



The presence of glycogen in depot fats can be demonstrated in a number 

 of other nutritional states, in addition to the early stages of carbohydrate 

 feeding following a period of undernutrition. Thus, it was found to occur 

 in rats trained to consume their entire daily ration in one hour, 119 in animals 

 fed and starved on alternate days, 455,471 in rats after excessive carbohydrate 

 consumption 120 and in rats which had received appropriate dosages of in- 

 sulin. 455 In newborn rats, the glycogen supply, which is present in adipose 

 tissues at birth, rapidly decreases, concurrently with the increase in fat in 



467 E. Gierke, Ergeb. allgem. Pathol., pathol. Anal. (Lubarsch-Ostertag), 11, Part 2, 871- 

 900 (1907). 



468 E. Gierke, Verhandl. dent, pathol. Ges., 10th meeting, Stuttgart, 1906, 182-185 (Jena, 

 1907). 



469 A. Hoffmann and E. Wertheimer, Arch. ges. Physiol. (Pfiilger's), 217, 728-746 

 (1927). 



470 E. Wertheimer, Arch. ges. Physiol. (Pfliiger's), 219, 190-201 (1928). 



471 E. M. MacKay and D. R. Drury, Am. J. Physiol, 182, 661-665 (1941). 



