Cholecystokinin expression in the developing and regenerating pancreas andintestine

In developmental terms, the endocrine system of neither the gut nor the pan creatic islets has been characterized fully. Little is known about the invo lvement of cholecystokinin (CCK), a gut hormone, involved in regulating the secretion of pancreatic hormones, and pancreatic growth. Here. we tracked CCK-expressing cells in the intestines and pancreata of normal mice (BALB/c ), Non Obese Diabetic (NOD) mice and interferon (IFN)-gamma transgenic mice , which exhibit pancreatic regeneration, during embryonic development, the postnatal period and adulthood. We also questioned whether IFN-gamma influe nces the expression of CCK. The results from embryonic day 16 showed that a ll three strains had CCK in the acinar region of pancreata, and specificall y in alpha cells that also expressed glucagon. However, in adulthood only B ALB/c and NOD mice continued this pattern. By contrast, in IFN-gamma transg enic mice, CCK expression was suppressed from birth to 3 months of age in t he pancreata but not intestines. However, by 5 months of age, CCK expressio n appeared in the regenerating pancreatic ductal region of IFN-gamma transg enic mice. In the intestine, CCK expression persisted from fetus to adultho od and was not influenced by IFN-gamma. Intestinal cells expressing CCK did not co-express glucagon, suggesting that these cells are phenotypically di stinct from CCK-expressing cells in the pancreatic islets, and the effect o f IFN-gamma on CCK varies depending upon the cytokine's specific microenvir onment.