The influence of selective pancreatic denervation on plasma insulin and glucose tolerance in dogs

The mechanism of reflex plasma insulin responses after oral stimulation and the influence of autonomic control on glucose- and meal -induced insulin secretion needs to be elucidated. Dogs with chronic pancreatic fistulas were studied two months after selective pancreatic denervation or bilateral truncal vagotomy and compared with fistulated controls. The normal glucose- and amino acid-independent insulinogenic reflex after an oral glucose load or after a meal was inhibited in the experimental groups. Glucose-related insulin secretion (oral or intravenous loads) and glucose tolerance were clearly reduced after vagotomy, but only partly diminished in the denervated animals. The plasma insulin increase after meat ingestion was inhibited in both experimental groups. It is concluded that the B-cells work under integrated tonic control of both the vagal and the sympathetic systems. Independent of this control, a vago-vagal insulinogenic reflex is initiated by enteric stimuli. These two mechanisms might be considered as part of the gastroentero-pancreatic axis in a broader sense.