A light microscopic study of the gastro-entero-pancreatic endocrine cells of the mink (Mustela vison).

Endocrine cells in the stomach, intestine and pancreas of the mink were investigated, using silver impregnation and immunohistochemical methods, and the following results were obtained. The stomach of the mink possesses a well-developed acid-secreting region which occupies about 70% of the gastric mucosa. Half of Brunner's glands whose excretory duct empties in the most proximal duodenum are located in the duodenal submucosa with the remainder in the pyloric submucosa. The area covered by the glands is 7.5 mm long in rostrocaudal direction. Endocrine cells are numerous in Brunner's glands, in the pyloric gland region and in the duodenum, while they are few in the colorectum. Somatostatin-immunoreactive cells are distributed throughout the whole GEP system, while gastrin-immunoreactive cells are located mainly in the pyloric gland region. Secretin-, motilin- and neurotensin-immunoreactive cells are found in the duodenum, jejunoileum and lower jejunoileum, respectively. Glucagon-immunoreactive cells are located mainly in the pancreatic islet and are distributed scarcely in the fundic gland region. A few glucagon-immunoreactive cells are also found in the middle portion of the jejunoileum. In addition to the somatostatin-immunoreactive cells, argentaffin, glucagon- and glicentin-immunoreactive cells in the fundic gland region and argentaffin and gastrin-immunoreactive cells in the pyloric gland region extend cytoplasmic processes along the basement membrane. This suggests a paracrine secretion of these cell types. A few open type cells which are stained with Hellerström-Hellman's or Sevier-Munger's method or are reactive to the somatostatin antiserum are found in the fundic gland region. A possible relation between the present observation of the endocrine cells and the eating habits of the mink is discussed.