AXTI-DIABETIC SUBSTAXCE 



519 



256 (2216) 



A rapid method of preparing the anti-diabetic substance of 



pancreas. 



By R. S. ALLEN, H. A. PIPER, C. P. KIMBALL and JOHN R. MURLIN. 



[From the Physiological Laboratory of the University of Rochester, 

 Rochester, New York.] 



As reported 1 at the last meeting of this branch, heating to 75° 

 and 80° C. for one-half hour does not destroy the anti-diabetic 

 substance extracted in acid aqueous media. The original ob- 

 servation of Murlin and Kramer that a potent extract could be 

 prepared by boiling dog's pancreas in 0.2N HC1 was confirmed 2 

 some time ago. Recently we have compared the yield of rabbit 

 units obtained on the one hand by grinding macerated pancreas 

 in 0.2N HC1 in a bacteria grinder for 15 hours and, on the other 

 hand, by heating to 75° C. for one hour or bringing just to boil- 

 ing temperature. 



Kimball, Piper and Allen 3 showed also at the last meeting 

 that the active substance is precipitated by complete saturation 

 with sodium chloride, and with either of the alcohols, methyl, 

 propyl, butyl or amyl when added to a solution in 80 per cent, 

 ethyl alcohol. For example, preparation No. 140, heated in 0.2N 

 HC1 to 75° C, cooled, strained through cheese cloth, neutralized to 

 P H of 4.1, and filtered, gave in two tests representing 10 gms. pan- 

 creas each, a fall of blood-sugar in normal rabbits of 44 and 62 

 milligrams. The second day the filtrate was precipitated by sat- 

 uration with sodium chloride, the precipitate taken up in 70 per 

 cent, alcohol, centrifuged to remove insoluble protein and re- 

 precipitated with 5 vols, amyl alcohol. The excess of amyl alco- 

 hol was evaporated off before a fan and the residue taken up in 

 sterile water. Equivalent doses representing 10 grams pancreas 

 now gave drops in blood-sugar in rabbits of the same size of 

 77 and 74 milligrams showing that all the potency had been re- 



1 Piper, H. A., Mattill, H. A., and Murlin, J. R., Proc. Soc. Exp. Biol. 

 Med.. 1923, xx, 413. 



2 Murlin, J. R., Clough, H. D., Gibbs, C. B. F., and Stokes, A. M., Jour. 

 Biol. Chem., 1923, lvi, 253. 



3 Kimball, C. P., Piper, H. A., and Allen, R. S., Proc. Soc. Exp. Biol. 

 Med., 1923, xx, 414. 



