Brockmann body

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As Brockmann body , Brockmannsche body , Brockmann bodies and, occasionally, as a main islands (English bodies Brockmann or principal islets ) are anatomical structures in most bone fish species referred consisting of endocrine tissues exist and whose main task the production and release of the hormone insulin in response from the blood sugar level . They were first described by Heinrich Brockmann in 1846 in the bullhead species Cottus scorpius and the cod species Gadus callarias .

Construction and function

In terms of their physiological function, the Brockmann bodies of the bony fish are similar to the Langerhans Islands of mammals , birds , reptiles and amphibians , which in their entirety are also referred to as "island organs". Unlike the islets of Langerhans but Brockmann bodies provide a concentrated to a few larger structures and the mesentery near the gallbladder is localized Island organ. In the islets of Langerhans, the insulin-producing beta cells are, however, together with certain other hormone-producing cells in the form of compact cell clusters in the pancreas . This consists of both exocrine tissue, which produces digestive enzymes , and the endocrine tissue of the islets of Langerhans, the number of which, depending on the species, ranges from several thousand in smaller mammals to up to a million in humans.

In contrast, Brockmann bodies are usually separate from the exocrine pancreas. However, the presence of exocrine tissue in the Brockmann corpuscles, a thin layer of exocrine cells around the Brockmann corpuscles or the deposition of the Brockmann corpuscles in the liver is also possible . Some fish, such as the gobies , have a single Brockmann body, while others, such as the bullheads, are paired. The presence of several Brockmann bodies or of additional smaller islands is also possible in some species. Larger Brockmann bodies are already recognizable with the naked eye as white or pink-colored round or oval structures. Analogous to the islets of Langerhans in mammals, the Brockmann bodies of bony fish contain not only beta cells but also cells that release glucagon (alpha cells), somatostatin (delta cells) and pancreatic polypeptide (PP or F cells).

Brockmann bodies are used in medical research as an experimental model for studies on islet cell transplantation , a surgical treatment of diabetes mellitus , as their extraction is significantly less complex than is the case with islets from mammals.

literature

  • JMW Slack: Developmental Biology of the Pancreas. In: Development. 121/1995. The Company of Biologists, pp. 1569-1580, ISSN  0950-1991
  • JH Youson, AA Al-Mahrouki: Ontogenetic and Phylogenetic Development of the Endocrine Pancreas (Islet Organ) in Fish. In: General and Comparative Endocrinology. 116 (3 )/1999. Elsevier, pp. 303-335, ISSN  0016-6480
  • DH Evans, JB Claiborne: The Physiology of Fishes. Third edition. CRC Press, Boca Raton 2006, ISBN 0-84-932022-4 , p. 284
  • EM Plisetskaya, TP Mommsen: Glucagon and Glucagon-Like Peptides in Fishes. In: Kwang W. Jeon (Ed.): International Review of Cytology. Volume 168. Academic Press, San Diego 1996, ISBN 0-12-364572-7 , pp. 187-243 (especially pp. 189-192)
  • The Endocrine Pancreas in Fish. In: SG Pierzynowski, R. Zabielski: Biology of the Pancreas in Growing Animals. Series: Developments in Animal and Veterinary Sciences. Volume 28. Elsevier Health Sciences, Amsterdam and New York 1999, ISBN 0-44-450217-3 , p. 444
  • JR Wright Jr., B. Pohajdak: Cell Therapy for Diabetes using Piscine Islet Tissue. In: Cell Transplantation. 10 (2) / 2001. Cognizant Communication, pp. 125-143, ISSN  0963-6897