EVIDENCE FOR AN INFLUENCE OF THE PERI-ARTERIAL HEPATIC NERVES ON BASAL INSULIN-SECRETION IN THE RAT

We studied the in vitro sensitivity of isolated pancreatic islets to g lucose and glucagon 1 week after in vivo micro-surgical denervation of the per-i-arterial hepatic nerves in the rat. Basal insulin secretion (at 3.3 mM glucose) was significantly higher in denervated than in sh am operated or control animals (137 +/- 27 muU/ml vs. 35 +/- 2 muU/ml, P = 0.004 and 58 +/- 15 muU/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 muU/ml vs. 211 +/- 6 muU/ml, P = 0.005), but not significantly vs. controls (273 +/- 41 muU/ml). In contrast, when the islets were stimulated with glu cagon (10(-9)-10(-5) M) at basal glucose concentrations (3.3 mM), the increment of insulin secretion was not significantly higher in the den ervated animals vs. control animals. Our findings indicate the existen ce of a neural control mechanism of basal insulin secretion from the p ancreatic islets mediated through the peri-arterial autonomic hepatic nerves.