The functional importance of sympathetic nerves to the liver and endocrine pancreas.

Sympathetic noradrenergic nerves, with their wellknown cardiovascular effects, have recently been found to influence several metabolic and hormone-releasing processes. Morphological investigations in man have revealed a dense sympathetic innervation of the liver parenchyma as well as sympathetic fibers among the endocrine cells in the islets of Langerhans. Functional studies both in animals and man have shown that electrical or reflex activation of the hepatic and pancreatic sympathetic nerve fibers causes an increased output of glucose from the liver as well as a stimulation of glucagon and an inhibition of insulin release from the pancreas. From these results we conclude that damage to sympathetic nerves should be avoided in abdominal surgery.