Pancreatic Secretory Response to Sham Feeding in Humans

Abstract

We studied the pancreatic secretory response to sham feeding alone or during secretin infusion with and without administration of atropine in 10 human subjects. The magnitude of the response to sham feeding was compared to the response to cholecystokinin octapeptide. Sham feeding alone did not significantly increase pancreatic bicarbonate or amylase secretion above basal values. During a background secretin infusion, there was a significant increase of bicarbonate and amylase output (p < 0.05) during sham feeding. The amylase response was approximately 50% of the maximal response to cholecystokinin octapeptide. In the tests with atropine and secretin, sham feeding still caused a significant increment in amylase and bicarbonate output. We conclude that (1) the pancreatic response to sham feeding is not clearly demonstrated without a background of secretin; (2) during secretin infusion sham feeding is a potent stimulant of pancreatic enzyme secretion, and (3) atropine had no significant effect on the pancreatic response to sham feeding under the conditions of this study.

Hyperglycemia Reduces Pancreaticobiliary Secretion in Response to Modified Sham Feeding in Humans

“…The present finding that sham feeding stimulates pancreatic enzyme secretion is in agreement with previous observations [13, 15, 16], although others have failed to show an increase in pancreaticobiliary output during cephalic stimulation [14, 23]. The reason for this discrepancy is not apparent but may be related to methodological differences such as duodenal perfusion with a recovery marker, aspiration or neutralization of gastric acid and secretin background infusion.…”

“…The cephalic phase of pancreatic secretion is assumed to be mediated by the vagus nerve with efferent cholinergic fibers acting directly or indirectly on the pancreas. Atropine abolishes pancreatic enzyme response to sham feeding, providing further evidence for muscarinic stimulation of the cephalic pancreatic response [13, 14, 15]. CCK is not involved in the regulation of the cephalic pancreatic response, since plasma CCK levels did not significantly increase during sham feeding, and CCK receptor blockade with loxiglumide does not affect the magnitude of the cephalic stimulated pancreatic exocrine response [15].…”

“…In fact, several arguments are in favor of an inhibitory effect of hyperglycemia on pancreaticobiliary secretion by suppressing the activity of the vagal-cholinergic system. First, in humans, basal and cephalic stimulated exocrine pancreatic secretions are predominantly regulated by vagal-cholinergic mechanisms [11, 12, 13, 14, 15, 16]. Second, it has been shown in animals that infusion of glucose suppresses vagal nerve activity [34].…”

“…The cephalic phase of pancreatic exocrine secretion, provoked by thought, sight, smell, taste or chewing of a meal, is assumed to be mediated completely by the vagal-cholinergic system [13, 14, 15, 16]. Cephalic stimulation with sham feeding increases pancreatic secretion up to 50% of maximum rate and thus may contribute considerably to meal induced pancreatic secretion [13].…”

Cephalic Stimulation of Gallbladder Contraction in Humans: Role of Cholecystokinin and the Cholinergic System

“…They were instructed not to swallow a single morsel of food. This method of sham feeding has been validated pre viously [16,17], In the real feeding study, subjects also chewed the meal for a 30-min period, but they now ingested it completely. Plasma gastrin levels were measured before and immediately after sham feeding to detect inadvertent ingestion of food particles.…”