title: Immunocytochemical localisation of the icosapeptide fragment of the PP precursor: a marker for 'true' PP cells?
abstract: Antisera were raised against the icosapeptide fragment of the pancreatic polypeptide (PP) isolated from the canine pancreas. They were used for the immunocytochemical study of the cellular localisation and distribution of the icosapeptide in the gut and pancreas of various mammals. The results indicate that PP and the icosapeptide coexist in the majority of the PP-immunoreactive cells in the pancreas of cat, dog, pig, monkey and man and in all the PP-immunoreactive cells in the stomach of the cat and dog. The icosapeptide does not seem to occur in cells or nerves containing PP-related peptides, such as peptide YY or neuropeptide Y. PP-immunoreactive cells devoid of the icosapeptide could be demonstrated in the large intestine. These cells are probably distinct from the pancreatic PP cell type, and the PP-immunoreactive material probably represents the homologous peptide YY rather than PP. The present findings support the view that the icosapeptide is part of the PP precursor and hence, only the cells containing immunoreactive icosapeptide in addition to immunoreactive PP are to be considered 'true' PP cells. The icosapeptide antisera did not stain PP cells in mouse, rat and guinea-pig, suggesting marked species variation in the amino acid sequence of the icosapeptide portion of the PP precursor.
mesh_terms: D000818:Animals; D002415:Cats; D004285:Dogs; D005260:Female; D005333:Fetus; D005455:Fluorescent Antibody Technique; D006168:Guinea Pigs; D006801:Humans; D007106:Immune Sera; D007515:Islets of Langerhans / Q000032:analysis; D008251:Macaca; D051379:Mice; D010179:Pancreas / Q000032:analysis; D010191:Pancreatic Polypeptide / Q000032:analysis*; D010446:Peptide Fragments / Q000032:analysis*; D011247:Pregnancy; D051381:Rats; D013045:Species Specificity; D013552:Swine
chemical_list: D007106:Immune Sera; D010446:Peptide Fragments; C040734:pancreatic eicosapeptide; D010191:Pancreatic Polypeptide