Society of Biological Chemists xxxi
tration to affect favorably all thc major symlptoms of diabetes
produced by depancrcatization. In several instances thie bloo0(
sugar was reduced to normal or lower by a single injection; thc
excretion of sugar is stopped by two or three irnjectiorns; and the
respiratory quotient may be raised at wvill by repeated injections.
When the perfusion fluid is made slightly acid more potent ex-
tracts are obtained. The name glucopyron is suggestedl as the onc
most appropriate for tile active antidiabetic substance however
obtained from the pancreas. There is no evidence that it is a
chalone in Schafer's sense: hence the name insulit suggested by
him is inappropriate.
SOME PROPERTIES OF AN ACTIVE CONSTITUENT OF PANCREAS
BY E. A. DOISY, MiICHAEL SOMOGYI, A.u P. A. SIIVAFFER.
(Fromrl tle Laboratory of Biological Chesistrly, llasingto Ulrniversitg
School of Medicine, St. Lo1ais.)
Insulin has been prepared from beef pancreas by modifications
of methods outlined by Banting and Best and by Collip. More
than fifty different preparations have been made and used is
work with dogs and rabbits, in in vitro experiments, and with
human diabetics, with marked success.
The active material has been purified andl corncentratcel to the
point that about 0.25 mg. of substance produces mnarked hypo-
glycemia and characteristic convulsions in rabbits weigbing about
1 kilo. This material is a white powder having the following
properties. It contains about 14 per cent nitrogen, atlld is free
from phosphorus; it gives distinct biuret reaction, faint reaction
with glyoxylic acid, and doubtfusl Millon's reaction. Its solu-
tions are levo-rotary. Its activity in large part withstands
boiling in 0.1 x HCl for 5 minutes. It is freely soluble in water
except at C, about 5 to 6, at which reaction it is precipitatled
(incompletely) from its solutions. It is soluble also in alcohol
except at its isoelectric point. It is fairly completely precipitated
from water solutions by one-half saturation ammoniumn sulfate.
The substance appears to be an albumose or globulin. Although
there appears to ble considerable uniformity in the relation between
activity antd weight of substance, in variouis purifiedl preparations