Morphological changes of pancreatic polypeptide immunoreactive cells in gastrointestinal tract and pancreas of mouse

Objective To observe the ontogeny,distribution,morphology and the quantitative changes of pancreatic polypeptide immunoreactive(PP-IR)cells in the gastrointestinal tract and pancreas during the development of mouse.Methods Immunohistochemical SP method were used to observe the morphological characteristics of PP-IR cells in gastrointestinal tract and pancreas of mouse.Results PP-IR cells were not found in the body of stomach,gastric antrum and small intestine from ED11 to day 45 after birth.PP-IR cells were found in pancreas at ED 17 and in colon at ED 18.From birth to mature of mouse,PP-IR cells increased gradually,and peaked in pancreas and colon at days 15 and 30 after birth,respectively.In pancreas,PP-IR cells were predominantly located in the islet.PP-IR cells in the mouse gastrointestinal tract and pancreas were various in the shape,and the immunoreactive positive processes of the cells extended between the adjacent cells.Conclusion Pancreatic polypeptide released from PP-IR cells might regulate the activities of the pancreas and the colon.In addition to endocrine,PP-IR cells might influence the functions of adjacent cells by paracrine.