Hormonal response to enteral feeding and the possible role of peptide YY in pathogenesis of enteral feeding-related diarrhoea.

Diarrhoea is a common complication of enteral feeding. Previous studies have demonstrated a secretion of water and electrolytes in the ascending colon during intragastric but not intraduodenal enteral feeding. The cause of this secretion is likely to be neurohumoral in origin. This study was designed to examine the hormonal responses to enteral feeding. In vivo segmental colonic perfusion studies were undertaken. Before and at hourly intervals during these studies serum was taken for estimations of neurotensin (NT), pancreatic glucagon (PG), peptide YY (PYY) and vasoactive intestinal polypeptide (VIP). During fasting there was a median ascending colonic absorption of water in all groups. During feeding there was a net secretion in the ascending colon in both gastric groups and in the high load duodenal group, but not in the low load duodenal group. During these studies the PYY levels remained unchanged from fasting in the low and high load gastric groups. In the low and high load duodenal groups the PYY levels increased. The NT levels increased only in the high load duodenal group. There were no other changes in NT or in PG or VIP levels either between fasting and feeding, or between the gastric and duodenal groups. PYY is known to stimulate intestinal absorption. The absence of a rise during intragastric feeding may be important in the underlying mechanisms of enteral feeding-induced colonic secretion and hence enteral feeding-related diarrhoea.