CHAPTER VI 



THE INTERNAL SECRETION OF THE PANCREAS 



THE most usually quoted example of a gland which has both 

 an internal and an external secretion is the pancreas. A 

 relation between diseases of the pancreas and diabetes has long 

 bean suspected, but Minkowski and Mehring first definitely 

 showed that complete removal of the pancreas in the dog, cat, 

 and pig is followed by diabetes having the usual symptoms of 

 that disease in man. That this is caused by the absence of an 

 internal secretion is proved by the facts that it does not occur 

 if the gland be left in situ and the duct tied, nor does it occur 

 if a portion of the pancreas be grafted in some situation remote 

 from its normal position (e.g., underneath the skin or in the 

 peritoneum). 



It is interesting to note that a dog dying from pancreatic 

 diabetes eats ravenously because of increased intensity of the 

 gastric hunger contractions. 



It has been observed that complete pancreatectomy in 

 pregnant bitches near term does not result in diabetes, although 

 there is serious general disturbance. 



How the internal secretion of the pancreas normally prevents 

 glycosuria is not olear. We can only say that it exerts some 

 influence upon the carbohydrate metabolism, either by favour- 

 ing the formation of glycogen in the liver from the glucose 

 taken to it by the portal vein, or by furthering the oxidation 

 of glucose in the tissues generally. 



Pfliiger confirmed the observation of Marcuse that extirpa- 

 tion of the pancreas in the frog produces the same symptoms 

 as in mammals. He also makes the further statement that 

 extirpation of the duodenum or separation of the duodenum 

 from the pancreas the blood-supply of the gland being left 

 intact has the same effect. Pfluger criticizes the ordinary 



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