The Endogenous Release of Pancreatic Polypeptide by Acid and Meal in Dogs

Abstract

The response of pancreatic polypeptide (PP) to testmeal (5 ml/kg) and intraduodenal acid (4 mEq HCl/5min) and its reaction to somatostatin (3.5 microgram/kg/h following bolus injection of 3.5 microgram/kg) was studied in dogs with chronic duodenal and gastric fistulae. In addition the influence of atropin (0.5 mg/kg/h) on acid-induced PP response was examined. PP was measured by radioimmunoassay pancreatic secretion by determinating volume, bicarbonate, protein, and enzyme in duodenal contents and pancreatic juice. Plasma PP increased significantly following intraduodenal application of testmeal and hydrochloric acid. Its release was completely suppressed by SST. Furthermore, PP response to intraduodenal acid was blocked by atropin. Exocrine pancreatic secretion of bicarbonate and protein was inhibited by somatostatin as well as atropin. Since PP was released following administration of testmeal and acid, both potent stimulators of pancreatotropic duodenal hormones, it may play an important role in the control of the entero-pancreatic axis. The effect of atropin indicates a cholinergic nervous component of PP release.

The Release of Pancreatic Polypeptide by Exogenous CCK in Man and Dog

“…Pancreatic polypeptide (PP) has been shown to be released following a meal [1]. The mechanism controlling PP release is still not well understood, but it appears that a cholinergic background is required for a nor mal PP response [2], We have recently ob served that the C-terminal octapeptide of cholecystokinin (CCK-OP) stimulated the re lease of PP in dogs [3] and that this release can be reduced by atropine.…”

“…Plasma PP concentrations were measured by radioimmunoassay according to methods previously described [1] (antihuman PP anti serum. human PP standards, and bovine PP for tracer were generous gifts of Dr. R.A.…”

The influence of bovine pancreatic polypeptide on pancreatic exocrine secretion in young calves

“…In dogs, the radioimmunoassayable level of pancreatic peptide in plasma (using antisera to human PP) was increased by feeding and tease feeding (Chance et al,1975). This increase was suppressed by somatostatin (Kayasseh et al, 1978). In man, human plasma PP level increased after protein or fat ingestion (Adrian et al, 1977).…”

Gastric acid secretion, intraduodenal pH and gastroenteropancreatic hormone release to bombesin in antrocolic transposition dogs.

“…Therefore, a low response of plasma PP after bombesin stimulation may be attributable to impairment of the vagal-cholinergic mechanism in ACT dogs. Intravenous infusion of gastrin (Guzman et al 1981) and acid in the duodenum (Kayasseh et al 1978) also stimulate PP release in dogs. With regard to the possible mechanism of PP release after bombesin stimulation in the present experiments, however, endogenous gastrin and gastric acid seem to have a minor role, becuse a low response of plasma PP after bombesin stimulation was observed in ACT dogs, which showed greater hypergastrinemia and gastric acid hypersecretion than in non-ACT dogs.…”