Abstract
With the insulin assay using hypophysectomized-adrenodemedullated rats the following facts were observed in dogs:
1. The transient increase of the plasma insulin concentration in the cranial pancre-aticoduodenal vein following intravenous glucose administration was abolished after bilateral sections of the splanchnic nerves, of the sympathetic trunks, of the vertebral nerves, or after bilateral stellate and caudal cervical ganglionectomy.
The rise of the concentration, however, was observed after transection of the upper thoracic spinal cord, after bilateral sections of the ansae subclaviae, of the directly connected branches of the stellate ganglia with the spinal nerves (C7, C8 and Thl), or after bilateral cranial cervical ganglionectomy.
2. The blood flow in the cran. pancreatico-duodenal vein was not significantly changed after bilateral section of the vertebral nerves or transection of the upper spinal cord.
3. No significant increase of the plasma insulin concentration was found following electric stimulation of the distal ends of the splanchnic nerves.
From these results the conclusion is that such sympathetic pathway as the splanchnic nerves, sympathetic trunks, stellate ganglia and vertebral nerves, is indispensable for the elevation of the plasma insulin concentration, and a possibility of the action of the nervous system as a centripetal reflex arc in insulin secretion was discussed.
Through all of these experiments no correlation was found between plasma insulin concentrations in the pancreatic vein and glucose tolerance.
