512 



Pituitary and Carbohydrate Metabolism 



Anterior pitviitary extract, administered to normal or to hypophysectomized 

 rats, in experiments of exactly similar type to those described above, reverses 

 the direction of the changes. In the hypophysectomized animal, the restora- 

 tion to normal by APE is not quite complete, but in normal animals the 

 changes are striking. There is a marked fall in the RQ and increased deposi- 

 tion of muscle glycogen, but not of liver glycogen. This fall in the RQ in 

 glucose-fed animals has been used as the basis of assay of APE for metabolic 



effects."" 



TABLE 1 



Disposition of Fed Glucose in Rats 



(4 hours after feeding) 



* Standard error. 



t Saline anterior pituitary extract, I ml. given intraperitoneally I to 2 hours before glucose feeding. 



Additional evidence that the anterior pituitary affects peripheral oxidation 

 of carbohydrate has been obtained in eviscerated or hepatectomized animals. 

 The first positive indication that APE had a peripheral action was obtained 

 by Marks,^^ who found that it prevented the deposition of muscle glycogen 

 following insulin administration in eviscerated cats. Himsworth and Scott^'^ 

 continued this work by determining the relative effects of APE and insulin 

 on the survival time of functionally hepatectomized rabbits. The data in table 

 2, taken from their paper, where the time between hepatectomy and the 

 occurrence of hypoglycemic convulsions measures inversely the rate of fall 

 of the blood sugar, shows that the APE prevented the hypoglycemic effects of 

 insulin in the absence of the liver. 



More recently, the metabolism of the hypophysectomized eviscerated prepa- 

 ration has been studied. Greeley" first determined that hypophysectomized 

 rabbits, in which the blood sugar falls very rapidly when they are fasted, re- 

 quire the administration of glucose at the rate of about 500 mg. per kilogiam 

 per hour to maintain normal blood-sugar levels. Of course, the normal rabbit 

 requires no extra glucose beyond that which it makes itself. Now this large 

 glucose requirement has been found to persist unchanged in the absence of 

 the liver or of the abdominal viscera, and it is several times the amount 

 needed by the normal eviscerated rabbit (Drury'*). This abnormally great 



