736 THE ENDOCRINE ORGANS, OR DUCTLESS GLANDS 



with the results of observations made on structures other than the blood 

 vessels. 



Other muscular structures excited by epinephrine are as follows: 

 (1) the dilator muscle of the pupils, especially after the nerve supply has 

 been destroyed by extirpation of the superior cervical ganglion; (2) the 

 sphincters of the pylorus and of the ileocecal valve; (3) the muscle fibers 

 of the spleen, the vagina, the uterus, the vas deferens, and the retractor 

 penis. Regarding the action on the uterus, however, it should be noted 

 that a different response may be obtained according to whether the 

 uterus is pregnant or not. The plain muscles of the orbit and globe of 

 the eye are sometimes excited by suprarenal extract, causing the eyes to 

 protrude, the palpebral fissure to become large and the third eyelid to 

 be retracted, changes which are very like those which develop as a 

 result of fright. 



Inhibitory effects of epinephrine on muscle are exhibited by the follow- 

 ing: (1) the muscle of the intestine; (2) the stomach; (3) the esophagus; 

 (4) the gall and urinary bladders. 



The effect of epinephrine in inhibiting the rhythmic contractions of 

 an isolated portion of the intestine in oxygenated Ringer's solution is a 

 very striking phenomenon, and one which, as we shall see, may be very 

 successfully employed for detecting small quantities of epinephrine. 



The effects of epinephrine on glandular structures are the same as those 

 which would be produced by stimulation of the sympathetic nerve supply 

 of the gland. Thus, the secretions of the lachrymal gland, the salivary 

 gland (in the cat), the mucous glands of the mouth and pharynx, the 

 gastric but not the pancreatic glands, can readily be shown to be 

 excited. 



From these results as a whole, it is evident that the effect of- epineph- 

 rine on muscles and glands is exactly the same as that which would be 

 produced by stimulation of their sympathetic nerve supply. This paral- 

 lelism of action between epinephrine and the sympathetic nervous sys- 

 tem becomes still more evident when we consider certain of the changes 

 in metabolism that follow administration of epinephrine. Injection of 

 epinephrine excites glycogenolysis in the liver so that hyperglycemia 

 and glycosuria become established, results which are also obtained by 

 stimulating the great splanchnic nerve. Intravenous injection of epineph- 

 rine causes the clotting time of the blood discharged from the liver 

 to be very materially shortened, an effect also produced by stimulating 

 the splanchnic nerve. 63 



As in the case of the blood vessels, the above results are obtained even 

 after the sympathetic nerves to the part have been allowed to undergo 

 degeneration, from which it is concluded that the tissues elaborate some 



