748 THE ENDOCRINE ORGANS, OR DUCTLESS GLANDS 



the circulation before it arrived at the place on which it is to act. More- 

 over, it has been shown that stimulation of the previously cut hepatic 

 nerve plexus (around the hepatic pedicle) in a normal animal produces 

 hyperglycogenolysis, in which case there can be no question of a hyper- 

 secretion of epinephrine. 



No doubt the adrenal glands have some important relationship to the 

 nerve control of the glycogenolytic process, for, in animals from which the 

 adrenal glands have been removed, stimulation of the hepatic plexus does 

 not produce hyperglycemia. From this result it would appear that the 

 presence of a certain amount of epinephrine in the blood is necessary for 

 the proper transmission of the nerve impulse from the sympathetic nerve 

 fibers to the liver cell. When the nervous system is stimulated in such 

 a way as to excite the glycogenolytic process, two effects both operat- 

 ing in the same direction with regard to the glycogenic function are 

 developed: the one, a hypersecretion of epinephrine, which activates 

 the sympathetic nerve endings, the other, the transmission of the nerve 

 impulse to the liver cell (Macleod and R. G. Pearce). 7 '* 



4. With the Pancreas. The function of the pancreas here concerned 

 is that of its supposed internal secretion from the Isles of Langerhans. 

 Since epinephrine readily produces glycosuria, and sinc'e excision of 

 the pancreas has the same effect, it has been natural to inquire whether 

 any relationship exists between the two glands, and some observers 

 have obtained results which they interpret as indicating that it does. 

 Certain observers even -state that glycosuria does not occur after the 

 injection if at the same time extract of pancreas is injected. It is al- 

 most certain, however, that these results are not trustworthy. Thus, 

 removal of the adrenal glands in an animal suffering from pancreatic 

 diabetes does not restore any of the lost power of utilizing glucose 

 during the few hours that the animal remains alive. 74 That some rela- 

 tionship may, however, exist is indicated by the fact that epinephrine 

 causes dilatation of the pupil when it is dropped into the eye of a per- 

 son suffering from diabetes, whereas it has no such effect in the normal 

 individual. 



