PARS GLANDULARIS AND METABOLISM 



pophysectomized animals toward changes in carbohydrate 

 metabolism caused by epinephrine.'^ 



In all other work epinephrine was administered subcuta- 

 neously. Obviously, then, if observations were made in well- 

 fed animals, differences in the reponse of normal and hy- 

 pophysectomized animals cannot be attributed to a funda- 

 mental change in the action of epinephrine, unless the factor 

 of deficient absorption has been ruled out. Cope (1937) and 

 Cope and Thompson (1937) used rabbits. They believed that 

 storage of hepatic glycogen does not follow the subcutaneous 

 injection of epinephrine, but they did find in a different series 

 of animals that the hormone causes an increase in the con- 

 centration of lactic acid in the blood comparable to that 

 produced before hypophysectomy. (It appeared that less 

 glycogen was formed by the liver from intravenously injected 

 lactate as a result of hypophysectomy.) The lactic acid of 

 the blood of hypophysectomized rats, which were fasted but 

 received no epinephrine, began to rise when the concentration 

 of sugar in the blood fell below 40 mg. per cent. Cope and 

 Thompson believed that hypophysectomy does not affect the 

 mobilization of the glycogen of muscle. Chaikoff and others 

 (i 935) used dogs for their experiments. They injected epineph- 

 rine subcutaneously and concluded that the response of 

 hypophysectomized animals — in respect of increase in the 

 concentration of sugar and lactic acid in the blood and of de- 

 crease in inorganic P — is indefinitely smaller than that of 



'^ Heinbecker and Weichselbaum (1937) found that the intraperitoneal injection 

 of epinephrine provokes hyperglycemia with equal effectiveness in normal and hy- 

 pophysectomized dogs, provided that the nutritional condition is good. 



CoUip, Thomson, and Toby (1936) injected epinephrine subcutaneously and 

 concluded that, as a result of hypophysectomy, hyperglycemia and reduction of 

 muscle glycogen are prevented but that restoration of the effects appears if anterior 

 pituitary extract be injected. The authors used rats. Bachman and Toby (1936) 

 reported that hypophysectomy interferes with the mobilization of glycogen in muscle 

 caused by the injection of epinephrine into rabbits. These authors injected the hor- 

 mone subcutaneously but sometimes observed a satisfactory hyperglycemic re- 

 sponse, if the liver contained an adequate amount of glycogen. 



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