Hosoda Hiroshi, Kojima Masayasu, Kangawa Kenji
Department of Biochemistry, National Cardiovascular Center Research Institute, Osaka, Japan.
J Pharmacol Sci. 2006;100(5):398-410. doi: 10.1254/jphs.crj06002x. Epub 2006 Apr 13.
Ghrelin, identified as an endogenous ligand for the growth hormone secretagogue receptor, functions as a somatotrophic and orexigenic signal from the stomach. Ghrelin has a unique post-translational modification: the hydroxyl group of the third amino acid, usually a serine but in some species a threonine, is esterified by octanoic acid and is essential for ghrelin's biological activities. The secretion of ghrelin increases under conditions of negative energy-balance, such as starvation, cachexia, and anorexia nervosa, whereas its expression decreases under conditions of positive energy-balance such as feeding, hyperglycemia, and obesity. In addition to having a powerful effect on the secretion of growth hormone, ghrelin stimulates food intake and transduces signals to hypothalamic regulatory nuclei that control energy homeostasis. Thus, it is interesting to note that the stomach may play an important role in not only digestion but also pituitary growth hormone release and central feeding regulation. We summarized recent findings on the integration of ghrelin into neuroendocrine networks that regulate food intake, energy balance, gastrointestinal function and growth.
胃饥饿素被鉴定为生长激素促分泌素受体的内源性配体，作为来自胃的促生长和促食欲信号发挥作用。胃饥饿素具有独特的翻译后修饰：第三个氨基酸的羟基（通常为丝氨酸，但在某些物种中为苏氨酸）被辛酸酯化，这对胃饥饿素的生物学活性至关重要。在负能量平衡状态下，如饥饿、恶病质和神经性厌食症，胃饥饿素的分泌会增加，而在正能量平衡状态下，如进食、高血糖和肥胖时，其表达会降低。除了对生长激素的分泌有强大作用外，胃饥饿素还刺激食物摄入，并向下丘脑调节核传导信号以控制能量稳态。因此，值得注意的是，胃不仅在消化中可能起重要作用，而且在垂体生长激素释放和中枢进食调节中也可能起重要作用。我们总结了关于胃饥饿素整合到调节食物摄入、能量平衡、胃肠功能和生长的神经内分泌网络中的最新研究结果。
