Regional distribution of pancreatic polypeptide cells in the 21-day fetal rat pancreas.

21-day fetal rat pancreata were stained with the unlabeled antibody peroxidase-antiperoxidase technique using bovine pancreatic polypeptide as the primary antibody. Total counts of pancreatic polypeptide cells were made over the entire pancreas. It was found that the head region contained the greatest number of pancreatic polypeptide cells with the body next and the tail having the smallest number. The pancreatic polypeptide cells of the body were concentrated in the portion closest to the distal duodenum. This distribution pattern seems to support the suggested role of pancreatic polypeptide on the physiological function of the digestive tract.