PHYSIOLOGY OF EPINEPHRINE 91 



blood pressure, 2) the pupil (in cats) of an eye (sensitized by- 

 previous extirpation of the superior cervical ganglion), 3) the 

 rate of the denervated heart, or 4) on the volume of the spleen 

 or limbs. 



The auto-assay method has been widely used particularly 

 with the denervated eye or heart as described in the following 

 sections. 



8. Denervated iris method. The so-called paradoxical eye 

 reaction 451 for assaying epinephrine depends upon the fact that 

 the pupil dilates after an intravenous injection of epinephrine. 

 The eye of the cat is utilized for this reaction after sensitizing 

 it to the action of epinephrine by extirpating the superior 

 cervical ganglion. At least several days should elapse after 

 the ganglionectomy before utilizing this preparation. The 

 transverse diameter of the pupil is measured and the dilatation 

 caused by the injection of the unknown solution is compared 

 with that obtained by injecting a known concentration of 

 epinephrine. 



Stewart and Rogoff 687 demonstrated the diversity in results 

 obtained in the assay of epinephrine by the auto-assay 

 method (using the paradoxical eye reaction) as compared to the 

 intestinal segment method. Although Cannon and Rapport 102 

 have critized the conclusions of Stewart and Rogoff, the experi- 

 ments of Sugawara 601 and others, also indicate that these two 

 methods of assay do not give concordant results. Suga- 

 wara showed that the auto-assay method gave results indi- 

 cating the presence of only about two-thirds as much epi- 

 nephrine in a given sample of blood as is obtained by using 

 the isolated intestinal segment of the rabbit. Similar dis- 

 parities are also obtained when the blood is assayed by the 

 paradoxical eye reaction of a second cat and compared with the 

 results obtained by the intestinal segment method. The 

 blood of the adrenal vein must exert, therefore, a more power- 

 ful inhibiting effect upon the movements of the intestinal strip 

 than can be accounted for by its epinephrine content or else 



