DIGESTIVE GLANDS 



123 



§4.111 



It is produced from the duodenal mucosa by the action of the 

 acid chyme entering from the stomach. Pavlov (1910) and others 

 shov^^ed that this stage in digestion initiates a copious flow of 

 secretion from the pancreas into the duodenum, and that this still 

 occurs after section of both the vagus and sympathetic nerve 



160 r HCl Secretin 



140 



120 



100 



^ 80 



^ 60 



40 



20 







-20 L 



n^nf±~ Sodium 



P'°°"S oleate Amino 

 acids 



Water Sol. 



starch Dextrose 



Ui 



iLji!: 



Saline Maltose 



Corn 

 oil 



Control 



10 8 

 5 3 



7 5| 8 

 4 3 4 



level 



7 5 4 7 5 5 I Tests 



4 3 3 4 3 3 Dogs 



n-rr 



5 5 I 



Fig. 4-4. Diagram showing the effectiveness of various substances 

 introduced into the lumen of the duodenum in inducing secretion 

 of bicarbonate from a transplanted pancreas. The collected pan- 

 creatic secretion indicates by its change in volume (ordinates) the 

 quantity of secretin released into the circulation from the duo- 

 denum. Under each substance three vertical bars represent three 

 consecutive 20 min collecting periods ; each result is the mean 

 of 4-10 tests, carried out on 3-5 dogs in each case. Acid and secretin 

 are equally effective ; peptones and amino acids much less so (from 

 Wang and Grossman, 1951). 



supply ; a completely denervated loop of the intestine of a dog, if 

 treated w^ith acid in the lumen, can start the pancreatic flow, so 

 long as the circulation is intact. The stimulus for pancreatic 

 secretion is shown, by this and other cross circulation and trans- 

 plantation experiments, to be due to a blood-borne factor, and 



