BY F. G. BANTINO AND C. H. BEST, TORONTO, CAN.
I N a previous paperl we have reported experiments which justify the con-
clusion that some constituent of the pancreas destroys the active principle
of the internal secretion of the gland when extracts are made of the gland by
the usual methods. To eliminate these digestive substances, extracts were
prepared from degenerated pancreatic tissue ten weeks after ligation of the
ducts of the pancreas by which time the acinar but not the insular cells are
said to have disappeared. From this material we secured small quantities
of very active extract. The question of a more rapid and economical method
of securing larger quantities of the extract soon became of prime importance.
Ibrahim2 could obtain no conclusive evidence of the presence of an active
proteolytic enzyme in the pancreas of the human fetus till after the fourth
month of intrauterine life. Carlson3 reported that in pregnant bitches near
term, complete pancreatectomy was not followed by severe glycosuria in
uncomplicated cases till the young were born. Allen4 was unable to confirm
this finding. The most natural interpretation of Carlson's result is that
the pancreas of the fetus furnishes to the mother an internal secretion which
is necessary for the metabolism of sugar. These facts coupled with the
evidence afforded by our previous experiments suggested the possibility that
the fetal pancreas might prove a source of an extract rich in internal secretion
and yet free from the destructive enzymes of pancreatic juice.
In order to test this hypothesis a quantity of pancreas was obtained from
fetal calves of less than five months' development. The tissue was macerated
in Ringer's solution, and the liquid filtered off. The filtrate was tested on
several different diabetic dogs and found to produce similar effects upon the
percentage sugar of the blood and on the sugar excreted in the urine as did
the extract prepared from degenerated pancreatic tissue. The extract was not
found to contain any proteolytic enzyme.
In this paper we are reporting two experiments in which such extracts
of fetal calf pancreas were used.
A total pancreatectomy was performed upon Dog 27 on November 14;
weight of the animal, 5 kgm. The effects of injections of the extract are
given in Table I.
Chart I is the graphic record of some interesting experiments performed
upon a dog (No. 33) from which the pancreas was removed on November 18,
'From the Department of Physiology, University of Toronto.