132 



G. 1ST. STEWAKT 



blood upon rabbit intestine (and uterus) segments (Fig. 4), but corrob- 

 orated theif results by two other methods which are spoken of as methods of 

 auto-assay, because the blood is not withdrawn, but its content of epineph- 

 rin is estimated by reactions elicited in the animal itself. In one of these 

 methods blood from the suprarenals is allowed to collect in a pocket of the 



inferior vena cava for a definite 

 time, and is then released while a 

 blood-pressure tracing is being 

 taken. A rise of pressure is ol> 

 tained, the amount of which is then 

 imitated by the injection of known 

 amounts of epinephrin (Fig. 5). 

 In the other method of auto-assay 

 the dilatation of the pupil (in cats) 

 of an eye, sensitized for epinephrin 

 by previous removal of the su- 

 perior cervical ganglion, is ob- 

 served when the suprarenal blood, 

 collected in the cava pocket, is re- 

 leased, and the reaction imitated 

 by injection of epinephrin. The 

 "adrenalin" solution of Parke, 

 Davis & Co. is assayed by the 

 colorimetric method of Folin, 

 Cannon and Denis and the epi- 

 nephrin given off by the adrenals 

 is always expressed in terms of the 

 base. 



The average output for 29 cats 

 (under urethane), the lumboad- 

 renal vein blood of which was as- 

 sayed on rabbit intestine segments, 

 was 0.00025 mgm. of epinephrij) 

 per kgm. of bodyweight per 

 minute, and for 16 etherized 



cats 0.0002 mgm. per kgm. per minute. The range in the different 

 animals was from 0.00015 to 0.00045 mgm. per kgm. per minute in the 

 urethanizcd animals and from 0.0001 to 0.0005 mgm. per kgm. per minute 

 in the etherized cats(e, s) (1917) (1919). The usual range is far narrower 

 than is indicated by these extreme limits. For the great majority of tho 

 results lie quite close to the mean. Thus for 25 out of the 29 urethanized 

 cats the first significant figure in the output is either 2 or 3. The concen- 

 tration of epinephrin in the suprarenal blood in the urethanized cats ranged 

 from 1:800,000 to 1:14,000,000 and in the etherized animals from 1:1,- 



Fig. 5. A sample of blood pressure trac- 

 ings used in an auto-assay of the epinephrin 

 liberated during splanchnic stimulation in 

 a cat. The right splanchnic was stimulated 

 in the abdomen after section of both 

 splanchnics. The blood from the supra- 

 renals was collected in a cava pocket, which 

 was then released. Stimulation began at 

 the point indicated on the signal line a 

 short time after closing of the pocket. Good 

 rise of pressure after opening the pocket at 

 12, due to epinephrin; 18 and 19, "adrena- 

 lin" injections to assay the amount of 

 epinephrin liberated; 18, 0.3 c.c. of "adren- 

 alin" (1:150,000) ; 19, 0.2 c.c. of the same 

 solution. (Reduced to two-thirds.) (After 

 Stewart and Rogoff, J. Pharm. & Exper. 

 Therap. ) 



