['The pancreas is the main target of the trophic effect of cholecystokinin (CCK), with a transient increase in cell proliferation and persistent effect on DNA content and weight gain when given continuously. Whether CCK exerts similar effects on the liver and biliary tract is not known. Most studies on this subject have hitherto been done in the rat. The aim of the present experiments was therefore to study the possible concomitant trophic effects of CCK on these three organs in a gallbladder-bearing animal, the hamster.', 'CCK-8S or the CCK-A receptor antagonist devazepide were infused subcutaneously by osmotic minipumps for 4 weeks in 11 and 7 hamsters, respectively. Fifteen animals served as untreated controls. One hour before sacrifice tritiated thymidine was injected intraperitoneally. Plasma was collected for determination of CCK and the pancreas, liver, common bile duct and gallbladder were excised. The pancreas and liver were weighed and processed for the contents of protein, DNA and water. Tissue specimens were taken for autoradiography.', 'The concentration of CCK in plasma increased fourfold during the infusion of CCK-8S. The pancreas and, to a lesser extent, the liver increased in weight, DNA and protein contents after infusion of CCK-8S, whereas the pancreas, but not the liver, decreased in weight and protein content after infusion of devazepide. Pancreatic amylase content was increased after CCK-8S treatment, but unaffected by devazepide. Labelling index of pancreatic acinar cells, hepatocytes and gallbladder epithelium was no different from that of controls after four weeks of infusion of CCK-8S or devazepide. A correlation was found between the concentration of plasma CCK on one hand and the weights and DNA contents in pancreas and liver on the other.'] Does cCK stimulate growth of both the pancreas and the liver?