Neurotensin modulates the composition of pancreatic exocrine secretions inchickens

The effects of neurotensin on pancreatic exocrine secretion were examined i n fasted, conscious White Leghorn hens. A cannula was surgically implanted in the central duct serving the ventral lobe of the pancreas in order to co llect pure pancreatic juice. Following recovery, neurotensin was infused in travenously at 3.6 or 10.8 pmol/kg*min. The volume and pH of the pancreatic secretions were recorded and total pancreatic protein concentration, amyla se, lipase, trypsin, and chymotrypsin activity were measured every 30 min f or 2 hr and compared to secretions following the infusion of 0.9% saline. O ur results demonstrated that neurotensin did not affect the pH nor the panc reatic juice protein concentration, but did increase secretion rate followi ng neurotensin infusion at 3.6 pmol/kg*min. Amylase activity was significan tly depressed during neurotensin infusions, while lipase (both pancreatic a nd carboxylester lipase) activity was significantly elevated. The ratio of amylase to lipase activity was especially depressed by neurotensin infusion at 10.8 pmol/kg*min. Insufficient secretory activity prevented a balanced statistical analysis of chymotrypsin activity, but from a pooled analysis, neurotensin had no effect on protease activity in the pancreatic juice. The se results support our current research indicating that neurotensin may be a hormonal regulator of postprandial lipid digestion in chickens. J. Exp. Z ool. 283:455-462, 1999. (C) 1999 Wiley-Liss, Inc.