THE EFFECT OF INSULIN ADMINISTRATION ON THE RESPONSE OF THE PANCREAS TO PARASYMPATHETIC STIMULATION

¹ The Department of Physiology, McGill University, Montreal, Canada

1. In the rabbit, the normal effect of electrical stimulation of the vagal nerves is to increase the flow of secretion from the pancreas and the concentration of enzymes in the juice.

2. Administration of insulin diminishes or reverses this effect, subsequent stimulation of the parasympathetic nerves producing either a smaller positive effect on the gland or a marked inhibition of the secretion.

3. This is not due to exhaustion of the acinous cells, since after insulin administration the injection of glucose or a large dose of pilocarpine or acetylcholine still produces an increased output of enzymes from the gland.

4. During insulin hypoglycæmia, if the vagi are intact, the output of lipase from the pancreas progressively diminishes, whereas when the vagi have been severed the output of lipase remains constant.

5. Some evidence was obtained that injection of glucose enhances the normal secretory effect of vagal stimulation on the pancreas.

The expenses of this investigation were defrayed by a grant given to the writer by the Banting Research Foundation of Toronto, whose help is hereby gratefully acknowledged.

I wish to express my appreciation of the helpful advice and criticism of Dr B. P. Babkin, under whose direction this work was carried out. I should like also to thank Dr D. L. Thomson for criticism of the manuscript of this paper. I am indebted to Miss J. F. Oswald for assistance in the preparation of the manuscript for press.