PARS GLANDULARIS AND METABOLISM 



of either glucose or insulin appeared both in normal and 

 in hypophysectomized dogs. 



Abnormalities in the deposition and degradation of glyco- 

 gen in hypophysectomized animals have already been re- 

 ferred to briefly. Bennett (1936) as well as Russell (1936) 

 determined the concentration of sugar in the blood and of 

 glycogen in the liver and striated muscle of normal and hy- 

 pophysectomized rats under various conditions. After a fast 

 of 8 hours, the operated rats metabolized much more of the 

 glycogen of the liver (95 per cent compared with 27 per cent 

 in normal rats) and of striated muscle (24 per cent compared 

 with 8 per cent). If the fast was prolonged to 18 hours, both 

 normal and operated animals had consumed most of the 

 hepatic glycogen, whereas a further loss of muscle glycogen 

 occurred only in hypophysectomized rats. These observa- 

 tions were made by Russell, who also reported that the chief 

 abnormality found in hypophysectomized rats fed 2 gm. 

 of starch within 8 hours after a fast of 18 hours was a low 

 concentration of glycogen in the liver. Likewise, after the 

 feeding of glucose, partly because of slow absorption, hy- 

 pophysectomized rats restore the glycogen of the liver and 

 striated muscle only slightly (Bennett). Bennett's results 

 are summarized in Table 6. His calculations of the propor- 

 tion of absorbed glucose converted into glycogen indicated 

 that the percentage so converted is much higher in normal 

 animals — especially in respect of hepatic glycogen. Cope 

 ( 1 937) has reported further experiments in rabbits from which 

 he concluded that hypophysectomy interferes with the endog- 

 enous formation of carbohydrate and that when hepatic 

 glycogen is exhausted, the concentration of sugar in the blood 

 rapidly falls to levels associated with the onset of convulsions 

 so that the animal, in this respect, behaves like a hepatecto- 

 mized animal. In the hypophysectomized animal the hepatic 

 glycogen appears to be only of exogenous origin. According 

 to Soskin and others (1935), the hypophysectomized dog, 



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