Immunocytochemical localization of hormone-producing cells within the pancreatic islets of the rainbow trout (Salmo gairdneri).

A histological study of the pancreatic islets in rainbow trout, Salmo gairdneri, was undertaken in which polypeptide hormones-producing cells were localized, using immunocytochemical staining techniques. Four different cell-types were identified in this manner. These were the insulin, somatostatin, pancreatic polypeptide and glucagon/gastric inhibitory polypeptide (GIP) cells. The glucagon/GIP cell was designated thus as antisera to both hormones cross-reacted with a common population of cells. A fifth cell-type, commonly referred to as a clear cell, was also identified although its secretory product is as yet undetermined. These functional cell types were compared to the standard tinctorial properties of pancreatic endocrine cells. The relationships of the various cell types with each other was also observed.