064 INTERNAL SECRETION ENDOCRINE GLANDS 



The relation of the nervous system to the adrenal medulla has been 

 further illustrated by comparison of the amount of epinephrin which 

 can be extracted from the two adrenals when the nerves of one have been 

 cut. Under the influence of anaesthetics and some other drugs, bac- 

 terial toxins, such as diphtheria toxin, etc., the epinephrin store is 

 markedly diminished in the gland whose nerve supply has been left 

 intact as compared with the other. 



For example, in a cat the fibres coming from the sympathetic to the 

 left semilunar ganglion, including the left splanchnic nerves, were cut, 

 and the animal allowed to recover. Several days later when it is known 

 that equality of epinephrin load in the two adrenals would have been 

 restored, morphin was administered to the animal, and after a few 

 hours it was killed, and the epinephrin in the adrenals assayed. The 

 left gland contained 0-28 milligramme, the right, o-ii milligramme. If 

 the animal had been suddenly killed without morphin, the two adrenals 

 would have been found to contain equal amounts of epinephrin. There- 

 fore the deficiency in the right gland must have been due to the fact 

 that it was not protected by section of its nerves. 



A similar deficiency has been found in the unprotected gland aftei 

 administration of a drug, /3-tetrahydronaphthylamine, after surgical 

 operations (post-operative deficiency), and in many other conditions. 

 When the animal recovers the deficiency is gradually made good, the 

 adrenal having the power of forming and storing epinephrin up to a 

 ce "tain point in the absence of its nerve supply, although it is unable 

 to liberate it into the blood. 



There is no foundation for the statement that emotional disturb- 

 ances, as fright or anger, cause a depletion of the epinephrin store of the 

 adrenals. 



Summary : The existence of a nervous mechanism through which 

 the gland is stimulated to secrete epinephrin into the blood can there- 

 fore be considered as definitely established. It is the function of the 

 epinephrin, once it has entered the circulation that is involved in doubt. 

 Although it is highly improbable that the concentrations necessary for 

 direct stimulation of sympathetic endings ever exist in the general mass 

 of the blood, it is quite possible that a ' sensitizing ' influence is exerted 

 by epinephrin upon the sympathetic peripheral mechanisms which 

 renders them more susceptible to nerve impulses originating in other 

 ways. The possibility of a more direct action of epinephrin upon the 

 chemistry of carbo-hydrate metabolism, particularly upon glycogenolvsis 

 or even upon glycogen formation has been emphasized by some writers. 

 But glycogen can be formed abundantly, and certain experimental 

 hyperglyccemias which depend upon the rapid transformation of 

 glycogen into dextrose can be produced after the epinephrin secretion 

 of the adrenals has been abolished. 



Chemistry and Formation of Adrenalin. It has been shown (Stolz, 

 Dakin) that adrenalin (C 9 H 33 NO 3 ) is a dioxyphenyl-ethanol-methy 

 lamin, 



CH 

 OH.C/\C.CH(OH).CH 2 NH.CH, 



OH.C\/CH 

 CH 



