ULTRASTRUCTURAL LOCALIZATION OF PANCREATIC POLYPEPTIDE IN HUMAN PANCREAS

Abstract

Human pancreatic polypeptide (HPP) was localized in surgically obtained human pancreas by immunocytochemical EM. HPP was localized to the secretory granules of cells distinct from the .alpha., .beta. or .delta. cells of endocrine islets. The PP cells in 10 patients surveyed were most frequently located in the periphery of the islets. Immunolocalization distinguishes a 5th endocrine cell type in human islets which is distinct ultrastructurally by its smaller granule diameter and lack of PP immunoreactivity.