Late postprandial pancreatic secretion periods in conscious dogs. Effect of vagotomy.

It is well established that, in the dog, the exocrine pancreatic secretion in response to food intake is a two-phased mechanism with a first phase during 0-4 h period and a second one during 8-12 h period. In the present study we have investigated the role played by the vagus nerve in the genesis of this late pancreatic hypersecretion (second phase) in dogs with truncal vagotomy and pyloroplasty. Truncal vagotomy totally suppressed the first phase of the pancreatic secretion; it did not abolish the second postprandial phase but it increased its latency by delay of 4 hours. In fact, during the 12-18 h period a pancreatic hypersecretory response was evidenced after vagotomy which appeared to be statistically significant as compared to basal values (P less than 0.001). Our results indicate that the vagus nerve does not play a role in the genesis of the late hypersecretory second phase.