Characterization of obestatin- and ghrelin-producing cells in the gastrointestinal tract and pancreas of rats: an immunohistochemical and electron-microscopic study.
Both ghrelin and obestatin are derived from preproghrelin by post-translational processing. We have morphologically characterized the cells that produce obestatin and ghrelin in new-born and adult Sprague-Dawley rats that were freely fed, fasted, or subjected to gastric bypass surgery or reserpine treatment. Tissue samples collected from the gastrointestinal tract and pancreas were examined by double-immunofluorescence staining, immunoelectron microscopy, and conventional electron microscopy. Obestatin was present in the stomach, duodenum, jejunum, colon, and pancreas. In the stomach, differences were noted in the development of obestatin- and preproghrelin-immunreactive (IR) cells on the one hand and ghrelin-IR cells on the other, particularly 2 weeks after birth. Preproghrelin- and obestatin-IR cells were more numerous than ghrelin-IR cells in the stomach, suggesting the lack of ghrelin in some A-like cells. Most obestatin-producing cells in the stomach were distributed in the basal part of the oxyntic mucosa; these cells co-localized with chromogranin A (pancreastatin) and vesicle monoamine transporters type 1 and 2, but not with serotonin or histidine decarboxylase. Immunoelectron microscopy revealed the obestatin- and ghrelin-producing cells to be A-like cells, characterized by numerous highly electron-dense granules containing ghrelin and obestatin. Some granules exhibited an even electron density with thin electron-lucent halos, suggestive of monoamines. Feeding status, gastric bypass surgery, and reserpine treatment had no obvious effect on the A-like cells. In the pancreas, obestatin was present in the peripheral part of the islets, with a distribution distinct from that of glucagon-producing A cells, insulin-producing beta cells, and cells producing pancreatic polypeptide Y. Thus, obestatin and ghrelin co-localize with an anticipated monoamine in A-like cells in the stomach, and obestatin is found in pancreatic islets.
Zhao
Chun-Mei
CM
Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway. chun-mei.zhao@ntnu.no
Furnes
Marianne W
MW
Stenström
Björn
B
Kulseng
Bård
B
Chen
Duan
D
D000818:Animals; D000831:Animals, Newborn; D053379:Chromogranin A; D019858:Enteroendocrine Cells / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D005215:Fasting / Q000378:metabolism; D015390:Gastric Bypass; D005753:Gastric Mucosa / Q000166:cytology / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000166:cytology* / Q000378:metabolism; D054439:Ghrelin / Q000378:metabolism*; D006640:Histidine Decarboxylase / Q000378:metabolism; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000166:cytology; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism; D008297:Male; D016253:Microscopy, Immunoelectron; D008954:Models, Biological; D010179:Pancreas / Q000166:cytology* / Q000378:metabolism; D010187:Pancreatic Hormones / Q000378:metabolism; D036361:Peptide Hormones / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism; D013270:Stomach / Q000166:cytology; D050493:Vesicular Monoamine Transport Proteins / Q000378:metabolism
D053379:Chromogranin A; D054439:Ghrelin; D010187:Pancreatic Hormones; D036361:Peptide Hormones; C493451:Slc18a1 protein, rat; C493454:Slc18a2 protein, rat; D050493:Vesicular Monoamine Transport Proteins; C505798:obestatin, rat; C050836:pancreastatin; D012701:Serotonin; D006640:Histidine Decarboxylase