Identification of glucagon-producing cells (A cells) in dog gastric mucosa

Abstract

An immunocytochemical technique using specific antiglucagon serum reveals the presence of glucagon-containing cells situated exclusively in the oxyntic glandular mucosa of the dog stomach. Electron microscope examination of the mucosa demonstrated endocrine cells containing secretory granules with a round dense core surrounded by a clear halb, indistinguishable from secretory granules of pancreatic A cells. Like the alpha granules of pancreatic A cells, the granules of these gastric endocrine cells exhibited a peripheral distribution of silver grains after Grimelius silver staining. Moreover, the granules of these cells were found to be specifically labeled with reaction product, using the peroxidase immunocytochemical technique at the ultrastructural level. Accordingly, these cells were named gastric A cells.These data suggest that the gastric oxyntic mucosa contains cells indistinguishable cytologically, cytochemicaUy, and immunocytochemically from pancreatic A cells. It is believed that gastric A cells are responsible for the secretion of the gastric glucagon.

An Ultrastructural Study on the Endocrine Pancreas of Caiman latirostris, with Special Reference to Pancreatic Motilin Cells.

“…The primary antisera used in this study were anti-porcine glucagon (donated by N. YANAIHARA, Shizuoka, GL-5, 1:1,000), anti-beefpork insulin (Immuno Nuclear Corp., Stillwater, Lot. 47291, 1:200), anti-human somatostatin (donated by S. ITO, Niigata, 1:500), anti-avian pancreatic polypeptide (donated by J. R. KIMMEL, Kansas City, Lance-10/5/81 Bleed, 1:1,000) and anti-porcine motilin (donated by N. YANAIHARA, R-1104, 1:500 (BAETENS et al, 1976) were computed to allow for sectioning artifacts. The degree of circularity (DC), an index of the shape of granules, was estimated from the perimeter (PM) and the area (A) of granules by the formula, DC=4rx (A-PM/2)/0.9PM2.…”

International Union of Pharmacology. XXXV. The Glucagon Receptor Family

“…Its primary structure is identical in most mammals including man, although some amino acid sequence changes are noted in glucagons from guinea pig or nonmammalian vertebrates (Irwin, 2001). Glucagon is synthesized mainly in the A-cells present at the periphery of the islets of Langerhans (Baum et al, 1962) and is also detected in specific cells in the stomach and intestine in some species (Baetens et al, 1976), as well as in specialized neurons of the central nervous system. Isolation of cDNAs encoding glucagon (Lund et al, 1982;Lopez et al, 1983) showed that the peptide is produced from a 160-amino acid precursor, proglucagon, which also contains two additional glucagon-like sequences at its carboxyl terminus (GLP-1 and GLP-2), which were subsequently shown to display specific biological activities (Drucker, 1998).…”

Class II G Protein-Coupled Receptors and Their Ligands in Neuronal Function and Protection

“…Glucagon is synthesized mainly in the α-cells at the periphery of the islets of Langerhan's (Baum et al, 1962). Glucagon can be detected in specific cells in the stomach and intestine in some species (Baetens et al, 1976), as well as in specialized neurons of the CNS. Isolation of cDNAs encoding glucagon (Lund et al, 1982) showed that the peptide is produced from a 160-amino acid precursor, proglucagon, which also contains two additional glucagon-like sequences at its carboxyl terminus, GLP-1 and GLP-2, which were subsequently shown to display specific biological activities (Drucker, 1998).…”