Acid in proximal and distal duodenum inhibits, but hyperosmolal solution does not inhibit pentagastrin-stimulated acid secretion in chronic gastric fistula rats.

In chronic gastric fistula (GF) rats, hyperosmolal 0.20 M HCl infused into a duodenal loop anastomosed to the jejunum (Roux-en-Y) produced a greater inhibition of the maximal acid response to pentagastrin than HCl or 1200 mosmol kg-1 solution of polyethylene glycol (PEG) alone, suggesting that HCl and hyperosmolal solution inhibit secretion by different mechanisms. In the present study on chronic GF rats with Thirty-Vella loops of the proximal or distal duodenum (bile and pancreatic ducts transplanted to the jejunum), perfusion of the proximal or distal loop with 0.20 M HCl significantly inhibited the maximal acid response to pentagastrin, but perfusion with hyperosmolal PEG solution did not alter the response. The results suggest different anatomical sites for the inhibitory mechanisms, sensitive to acid and hyperosmolal solution.