Characterisation of gastric ghrelin cells in man and other mammals: studies in adult and fetal tissues

Abstract

Ghrelin is a new gastric peptide involved in food intake control and growth hormone release. We aimed to assess its cell localisation in man during adult and fetal life and to clarify present interspecies inconsistencies of gastric endocrine cell types. A specific serum generated against amino acids 13-28 of ghrelin was tested on fetal and adult gastric mucosa and compared with ghrelin in situ hybridisation. Immunogold electron microscopy was performed on normal human, rat and dog adult stomach. Ghrelin cells were detected in developing gut, pancreas and lung from gestational week 10 and in adult human, rat and dog gastric mucosa. By immunogold electron microscopy, gastric ghrelin cells showed distinctive morphology and hormone reactivity in respect to histamine enterochromaffin-like, somatostatin D, glucagon A or serotonin enterochromaffin cells. Ghrelin cells were characterised by round, compact, electron-dense secretory granules of P/D(1) type in man (mean diameter 147+/-30 nm), A-like type in the rat (183+/-37 nm) and X type in the dog (273+/-49 nm). It is concluded that, ghrelin is produced by well-defined cell types, which in the past had been labelled differently in various mammals mostly because of the different size of their secretory granule. In man ghrelin cells develop during early fetal life.

Vagal stimulation exaggerates the inhibitory ghrelin response to oral fat in humans

“…Various gastric secretory and hormonal functions are sensitive to the chemical properties of food within the stomach (McIntosh 1985, Hakanson et al 1986). However, gastric ghrelin-producing cells situated at the base of the mucosal layer are primarily of the closed type, and as such, are not in direct contact with the gastric lumen (Date et al 2000, Rindi et al 2002, Sakata et al 2002. Furthermore, prevention of gastric emptying of glucose in rodents abolishes the suppression of ghrelin normally seen following oral glucose (Williams et al 2003).…”

Effects of growth hormone secretagogues on the release of adenohypophyseal hormones in young and old healthy dogs

“…Thus, structural heterogeneity of ghrelin among species seemed minor, and a rather functional homogeneity in various mammalian species could be expected. GhrelinÕs expression is restricted to the X/A-like cells, or Ghr-cells, of the oxyntic gland (Date et al, 2000;Rindi et al, 2002).…”

Immunohistochemistry grelinpositive cells in the pancreas islets of the rat

“…Other authors confirm these results (6,16). Some investigators have reports for expression of ghrelin-positive cells in the rat (17,18) and other authors described a characterization of gastric ghrelin cells in adult and fetal tissues of human and other mammals (19).…”