Insulin and Blood Sugar 



515 



254 (2214) 



Studies on the physiology of the liver. VII. The effect of insulin 

 on the blood sugar following total and partial removal 

 of the liver. 



By FRANK C. MANN and THOMAS B. MAGATH. 



[From the Division of Experimental Surgery and Pathology, The 

 Mayo Foundation, and Section on Clinical Laboratories, 

 Mayo Clinic, Rochester, Minnesota.] 



Previously we have shown that the total removal of the liver 

 is followed by (1) a rapid decrease in blood-sugar, (2) always 

 accompanied by a characteristic group of symptoms, and (3) 

 the administration of glucose which abolishes the symptoms, 

 temporarily restoring the animal to the normal state. All of 

 this is comparable to what happens when a large dose of insulin 

 is administered to a normal animal. 



The problem investigated is the role the liver plays in the 

 effect of insulin. Therefore, insulin was administered before 

 and after the total removal of the liver in dogs. Removal of 

 the liver did not affect the sharp precipitate drop in the blood- 

 sugar after administration of insulin. Whereas injecting glu- 

 cose in an animal with its liver intact during the condition of 

 insulin hypoglycemia restores the sugar level permanently, after 

 the liver is removed no permanent level can be maintained 

 despite frequent large doses of glucose. 



The same experiments were carried out on dogs before and 

 after partial removal of the liver. While the same sharp drop 

 in blood-sugar occurs after giving very small doses of insulin, 

 there is a slow restoration of the curve, even though only 20 

 per cent, by weight of the liver remains. 



From these experiments we conclude that the symptoms asso- 

 ciated with hypoglycemia following the administration of in- 

 sulin do not differ essentially from those we noted in association 

 with the total removal of the liver, and the action of glucose 

 seems to be identical in the two conditions. The effect of large 

 doses of insulin in producing hypoglycemia is not changed by 

 the total removal of the liver, nor is the hypoglycemic action 

 of small doses of insulin modified by partial (60 to 80 per cent.) 

 removal of this organ. However, the liver is necessary for the 

 permanent restoration of the sugar level. 



