Physiology of Finfish and Shellfish (2+1)

5.2.11. Islets of langerhans or Endocrine Pancreas

Pancreas is a mixed gland. It comprises both, exocrinal and the endocrinal parts. The endocrine pancreas is present in most fish as islet of Langerhans or Brockman bodies. It arises from the endodermal lining of embryonic foregut. Islet of Langerhans is present near gall bladder or spleen. In some species the islets are very large and may be grossly visible. During the spawning season the size and number of islet will increase in some fish. It consists of 3 types of cells- alpha cells, beta cells and D cells. Alpha cells secrete glucagon hormone which control blood sugar level. Insulin released by beta cells also control glucose level and function of D cell are still unknown.

(A germ layer, occasionally referred to as a germinal epithelium, is a group of cells, formed during animal embryogenesis.