Cytologic observations on the pancreatic islets with reference to some endocrine-like cells of the gastrointestinal mucosa

Some findings obtained from cytological studies on the pancreatic islet of man and different animal species by applying several appropriate methods are reported. Three islet cell types were found to be simultaneously demonstrated by toluidine blue after methylation and saponification of tissue sections; metachromasia appeared to be in some way a constant finding of argyrophil D-cells which, at least in duck and man, displayed also a weak PAS-positivity. No one of the three insular cell types was found to show all the morphologic patterns of enterochromaffine cells, nor enterochromaffine cells showed all the patterns of insular cells. The existence of possible morphologic relationships between insular A-cells and some endocrine-like cells in fundic mucosa and, on the other hand, between argyrophil D-cells and some cells in antro-pyloric mucosa of the stomach is emphasized.