Ghrelin is a peptide predominantly produced by the stomach. Ghrelin displays strong GH-releasing activity. This activity is mediated by the activation of the so-called GH secretagogue receptor type 1a. This receptor had been shown to be specific for a family of synthetic, peptidyl and nonpeptidyl GH secretagogues. Apart from a potent GH-releasing action, ghrelin has other activities including stimulation of lactotroph and corticotroph function, influence on the pituitary gonadal axis, stimulation of appetite, control of energy balance, influence on sleep and behavior, control of gastric motility and acid secretion, and influence on pancreatic exocrine and endocrine function as well as on glucose metabolism. Cardiovascular actions and modulation of proliferation of neoplastic cells, as well as of the immune system, are other actions of ghrelin. Therefore, we consider ghrelin a gastrointestinal peptide contributing to the regulation of diverse functions of the gut-brain axis. So, there is indeed a possibility that ghrelin analogs, acting as either agonists or antagonists, might have clinical impact.

中文翻译：

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ghrelin的生物学，生理学，病理生理学和药理学方面。

Ghrelin是主要由胃产生的肽。生长素释放肽显示出强的GH释放活性。该活性由所谓的GH促分泌素受体1a型的激活介导。已经显示该受体对合成的，肽基和非肽基GH促分泌素家族是特异性的。ghrelin除了有力的GH释放作用外，还具有其他活动，包括刺激乳养和皮质营养功能，影响垂体性腺轴，刺激食欲，控制能量平衡，影响睡眠和行为，控制胃动力和胃酸分泌，对胰腺外分泌和内分泌功能以及葡萄糖代谢的影响。ghrelin的其他作用是心血管作用和肿瘤细胞增殖调节以及免疫系统的调节。因此，我们认为ghrelin是一种胃肠道肽，有助于调节肠脑轴的各种功能。因此，确实存在作为激动剂或拮抗剂的ghrelin类似物可能具有临床影响的可能性。