70 



Scientific Proceedings (125) 



32 (1992) 



Properties and methods of preparation of the anti-diabetic sub- 

 stance (glucopyron) generated by the pancreas. 



By JOHN R. MURLIN. 



[From the Physiological Laboratory of the University of Roches- 

 ter, Rochester, N. Y.] 



Repetition of several older methods of extraction of pan- 

 creas proved that with very slight modification any one of them 

 was adequate to demonstrate the presence of the anti-diabetic 

 substance. The essential steps in its preparation are : ( 1 ) de- 

 struction of trypsin; (2) precipitation of extraneous proteins; 

 (3) concentration; and (4) removal of irritant substances. 

 Banting 1 and Macleod 2 appear to have adopted exclusively the 

 method of alcoholic extraction and have given the name insulm 

 to the alcoholic extract. Just as potent and non-toxic extracts 

 may be prepared with aqueous media. The active substance is 

 not all in the final precipitate with absolute alcohol as stated by 

 Collip 3 . It is non-dialyzable through vegetable parchment in four 

 hours' immersion in running water; it is not precipitated by most 

 of the ordinary reagents employed for the precipitation of pro- 

 teins. It withstands boiling for 5 minutes in acid (N/10) media; 

 and it may be adsorbed on several different reagents commonly 

 used for this purpose. 



Proof that an aqueous extract given with small amount of 

 alkali (N/20 NaOH) by stomach tube will cause oxidation of 

 sugar in the depancreatized dog was given by Kramer 4 and the 

 writer in 1916. For the active substance itself (not the entire 

 alcoholic extract) however obtained and whatever its chemical 

 nature the name Glucopyron (Glykos, sugar and Pyron, burning) 

 is suggested. 



i Banting and Best, Journ. of Lab. and Clin. Med., 1922, vii, 464. 



* Macleod et al, Amer. Journ. of Physiol, 1922, lxii, 162. 

 > Collip, J. B., Trans. Roy. Soc. of Canada, 1922, xvi. 



* Murlin and Kramer, Journ. of Biol. Chem., 1916, xxvii, 516. 



