PHYSIOLOGY OF ADIPOSE TISSUE 619 



these tissues. 472 - 473 Finally, Hausberger and Gujot 473 demonstrated the 

 presence of glycogen granules in adipose tissue after the suture of nerves to 

 this tissue. 



The extent of deposition of glycogen varies in the different fat depots. 

 It is highest in the interscapular brown fat tissues of the rat, where the 

 concentration may be within the same range as in the liver. The adipose 

 tissue in the mesenteric wall is likewise high in glycogen, while the lowest 

 amounts occur in groin fat and in perinephric fat. 401 



Wertheimer and Shapiro 401 are of the opinion that glycogen is synthesized 

 in the adipose tissue. Otherwise it must be carried in the blood stream to 

 the fat depots, and must then diffuse through the cell membranes. How- 

 ever, well-preserved histological preparations of adipose tissue contain 

 glycogen only within the cells, and not in the intercellular spaces. These 

 facts can best be explained on the basis of the assumption that glycogen 

 synthesis occurs in situ. Since glycogen appears in such tissues only when 

 fat synthesis is most active, it is believed that its occurrence there is di- 

 rectly concerned with fat synthesis, in which it may be acting as an inter- 

 mediary product. That this is the main function of the adipose tissue 

 glycogen is shown by the fact that it cannot serve as a source of blood glu- 

 cose, as is the case with glycogen deposited in other tissues. 122 



(5) Normal Metabolism in Adipose Tissue 



There is general agreement that adipose tissue exhibits a definite 

 metabolism characteristic of living protoplasm, rather than an absence of res- 

 piration, as one would expect if it were simply dead storage tissue. The 

 respiratory quotient of adipose tissue has been reported 474 as 1.0 when it is 

 obtained from normally fed or fasted animals, and over unity, 474 ' 475 espe- 

 cially when glucose is added, 122 in which case it is reported as 1.15, or in 

 adipose tissue containing glycogen, 122 when the figure is 1.27. In fact, 

 Mirski 122 reported that a high R.Q. was maintained for many hours in 

 glycogen-containing adipose tissue, and that a value as high as 1.6 was some- 

 times noted. These high R.Q. levels are characteristic when a transforma- 

 tion of carbohydrate to fat is taking place (see page 539) . They offer con- 



472 F. X. Hausberger and O. Gujot, Arch, exptl. Pathol. Pharmakol. (A aunyn-Schmiede- 

 berg's), 187, 655-662 (1937). 



473 F. X. Hausberger and O. Gujot, Arch, exptl. Pathol. Pharmakol. (A ' aunyn-Schmiede- 

 berg's), 187, 647-654 (1937). 



474 G. Scoz, Arch. sci. biol. (Italy), 17, 262-273 (1932). 



475 H. Ruska and A. Quast, Arch, exptl. Pathol. Pharmakol. (Naumjn-Schmiedeberg's), 

 179,217-225 (1935). 



