Characterization and species differences in gastric ghrelin cells from mice, rats and hamsters

Abstract

Ghrelin is a newly identified gastric peptide hormone that has various important functions, including growth-hormone release and appetite stimulation. Ghrelin-immunoreactive cells (ghrelin cells) are characterized by X-type endocrine cells in the rat stomach. In the present study, we analysed ghrelin cells in fundi of stomach from ICR mice and Syrian hamsters immunohistochemically, immunoelectron microscopically and morphometrically, and compared the results with those from Wistar rats. Immunohistochemistry revealed that ghrelin cells were sparsely distributed in the proper gastric glands in all species. The number of ghrelin cells per unit area in hamsters was significantly lower than that in rats. Immunoelectron microscopy detected ghrelin immunolabelling in granules in the X-type endocrine cells. However, the diameter of granules in the hamsters was significantly smaller than that in the mice and rats. Gastric ghrelin contents were determined by radioimmunoassay, and levels in the hamsters were significantly lower than those in mice and rats. The results from mice were identical to those from rats. In conclusion, gastric ghrelin cells in mice and hamsters are characterized by X-type endocrine cells, as has been observed in rats. However, the data indicated that gastric ghrelin production was lower in hamster than in mouse or rat.

Distribution of ghrelin-positive mast cells in rat stomach

“…Since tryptase is wellknown marker for MCs [52], we performed double immunofluroescent staining for ghrelin with tryptase to confirm that both CTMCs and MMCs express ghrelin (Figure 1(a,b) (Figure 2(a-c)). This finding allowed us to suggest that MCs are another cell type within the rat gastric wall capable to produce ghrelin similarly to A/X cells [31,32,34]. [49] who reported that toluidine blue is a universal marker for all MCs [49].…”

“…[27][28][29][30][31][32][33][34][35][36][37][38][39][40]41] Ghrelin is known to be an endogenous ligand for the growth hormone secretagogue receptor (GHS-R) 1a, capable of stimulating growth hormone release from the pituitary gland. This peptide hormone has been obtained from rat and human stomachs [27].…”

“…Additionally, ghrelin is involved in many physiological processes, including control of gastric motility and acid secretion in animals and humans [29,30]. Recent studies using immunohistochemistry, immunoelectron microscopy and in situ hybridisation analyses indicate that in the rat stomach, ghrelin is produced mainly by X cells [31][32][33][34]. HandjievaDarlenska et al [35] investigated the effect of insulin and glucose administered in the third ventriculum on leptin and ghrelin expression in the hypothalamus, and elucidated the mechanisms of leptin resistance in obese rats.…”

Effects of short term genotropin (rgGH) subcutaneous injection on active ghrelin concentration in rat plasma, stomach, kidney & pancreas. (c2007)

“…The ghrelin-containing cells are a distinct endocrine cell type found in the mucosal layer of the stomach and are more abundant in the fundus than in the pylorus (Date et al, 2000;Rindi et al, 2002;Yabuki et al, 2004). Four different types of endocrine cells have been identified in the stomach mucosa: ECL, D, enterochromaffin (EC), and X/A-like cells (Davis, 1954;Capella et al, 1969;Solcia et al, 1975).…”

“…Four different types of endocrine cells have been identified in the stomach mucosa: ECL, D, enterochromaffin (EC), and X/A-like cells (Davis, 1954;Capella et al, 1969;Solcia et al, 1975). The X/A-like cells contain compact, round, electron-dense granules that are filled with ghrelin (Date et al, 2000;Dornonville de la Cour et al, 2001;Yabuki et al, 2004). In adult oxyntic glands, the X/A-like cells account for approximately 20% of the endocrine cell population.…”