Trophic Effect of Cholecystokinin-Pancreozymin on Pancreatic Acinar Cells from Rats of Different Ages

Abstract

The trophic effect of CCK-PZ [cholecystokinin-pancreozymin] was evaluated at different times during postnatal development of the rat exocrine pancreas. The pancreas possess growth capabilities that can be activated by the duodenal hormones CCK-PZ in adult rats. CCK-PZ can probably provoke hyperplasia in younger animals, those at the age of puberty (47 days). When the treatment was given immediately after weaning (26 days) and on animals still being nursed by their mothers (11 days), hyperplasia following CCK-PZ was moderate. The kinetics of the hyperplastic and hypertrophic effects of chronic administration of CCK-PZ were presented. Hyperplasia is moderate in 11 and 26 day rats while well established in older animals (47 and 82 days). Hypertrophy cannot be detected in suckling rats (11 days) but is most evident at 26 days since the concentrations of all the parameters studied, with the exception of lipase, are significantly increased. In the 47 day old and adult rats CCK-PZ provokes a selective augmentation in the concentration of RNA and chymotrypsin. The trophic effects of the duodenal hormone exist but vary in intensity and specificity with the age of the animal.