Evidence for an influence of the peri-arterial hepatic nerves on basal insulin-secretion in the rat.

We studied the in vivo sensitivity of isolated pancreatic islets to glucose and glucagon 1 week after in vivo micro-surgical denervation of the peri-arterial hepatic nerves in the rat. Basal insulin secretion (at 3.3 mM glucose) was significantly higher in denervated than in sham operated or control animals (137 +/- 27 microU/ml vs. 35 +/- 2 microU/ml, P = 0.004 and 58 +/- 15 microU/ml, P = 0.041, respectively). Also after stimulation with 13.3 mM glucose, insulin secretion was significantly higher in denervated cf. to sham operated animals (388 +/- 50 microU/ml vs. 211 +/- 6 microU/ml, P = 0.005), but not significantly vs. controls (273 +/- 41 microU/ml). In contrast, when the islets were stimulated with glucagon (10(-9)-10(-5) M) at basal glucose concentrations (3.3 mM), the increment of insulin secretion was not significantly higher in the denervated animals vs. control animals. Our findings indicate the existence of a neural control mechanism of basal insulin secretion from the pancreatic islets mediated through the peri-arterial autonomic hepatic nerves.