Action of pirenzepine, a new muscarinic antagonist drug, on human pancreatic secretion.

The action of a new muscarinic antagonist drug on the pancreatic secretion has been studied in 12 healthy subjects. A stable pancreatic secretory plateau was obtained with submaximal hormonal stimulation (0.125 CU/kg/h secretin: 30 ng/kg/h caerulein). The highest dose of pirenzepine (40 mg) inhibited both volume and enzymatic concentration and output (-72.2% and -77.9% of plateau value for chymotrypsin and lipase output, respectively, 30 min after pirenzepine injection). The inhibition appeared immediately, lasted for more than 60 min, and was dose-related. The calcium dose-response curve paralleled those of lipase and chymotrypsin outputs. These results were comparable to those obtained with other anti-acetylcholine drugs and may be associated with the action of certain doses of ethanol on pancreatic secretion. In contrast, the lowest pirenzepine dose used (10 mg) induced a delayed stimulation of bicarbonate output, and bicarbonate concentration was not altered.