Release of cholecystokinin by acid (38562).

In dogs with pancreatic fistulas, the amount of CCK released by acid in the intestine was estimated by determining how much exogenous CCK had to be fiven to mimic the pancreatic protein response. Duodenal infusion of 16 mmole/hr of HCl with a high background dose of intravenous secretin stimulated pancreatic protein secretion to about the same degree as 0.5 unit/kg-hr of exogenous CCK; the same acid load without secretin background gave a response equivalent to about 0.7 unit/kg-hr of CCK. Expressed as fractions of their respective doses for half maximal response, acid releases almost five times more secretin than CCK.