Dynamics of cholecystokinin-like, secretin and somatostatin immunoreactivity of blood plasma and extracts of duodenal mucosa, frequency of acute pancreatitis (AP) after the resection of the duodenum was studied on not purebred dogs. Rising of a secretin concentration in blood plasma after the clinoid resection of the duodenum, accompanied by decreasing of its concentration in duodenal mucosa, was revealed. Decreasing of cholecystokinin concentration in a neutral extract was revealed. In 24 hours alter resection of the duodenum AP was observed in 38% of cases, infusion of the lorglumide was reduced the frequency of this complication up to 6.2% (p<0.05).