Endocrine portion Size number Distribution Function A cells large 20% Peripheral glucagon B cells small% center insulin A D cells 5 mong somatostatin and b cells PP cells: pancreatic polypeptide Other cells G cells: gastrinSize number Distribution Function A cells large 20% Peripheral glucagon B cells small 75% center insulin D cells 5% Among A and B cells somatostatin Endocrine portion Other cells PP cells: pancreatic polypeptide G cells: gastrin