Sun Yuxiang, Asnicar Mark, Smith Roy G
Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA.
Neuroendocrinology. 2007;86(3):215-28. doi: 10.1159/000109094. Epub 2007 Sep 26.
Ghrelin, an acylated 28-amino-acid peptide, is an endogenous ligand of the growth hormone secretagogue type 1a (GHS-R1a). Ghrelin is best known for its hypothalamic actions on growth hormone-releasing hormone neurons and neuropeptide Y/agouti-related peptide neurons; however, ghrelin affects multiple organ systems and the complexity of its functions is only now being realized. Although ghrelin is mainly produced in the stomach, it is also produced in low levels by the hypothalamus and by most peripheral tissues. GHS-R1a is expressed predominantly in the anterior pituitary gland, at lower levels in the brain including hypothalamic neurons that regulate feeding behavior and glucose sensing, and at even lower levels in the pancreas. A reciprocal relationship exists between ghrelin and insulin, suggesting that ghrelin regulates glucose homeostasis. Ablation of ghrelin in mice increases glucose-induced insulin secretion, and improves peripheral insulin sensitivity. This review focuses on the newly emerging role of ghrelin in glucose homeostasis and exploration of whether ghrelin is a potential therapeutic target for diabetes.
胃饥饿素是一种含有28个氨基酸的酰化肽，是生长激素促分泌素受体1a型（GHS-R1a）的内源性配体。胃饥饿素最为人所知的是其在下丘脑对生长激素释放激素神经元和神经肽Y/刺鼠相关肽神经元的作用；然而，胃饥饿素会影响多个器官系统，其功能的复杂性直到现在才被认识到。虽然胃饥饿素主要在胃中产生，但下丘脑和大多数外周组织也会少量产生。GHS-R1a主要在前脑垂体中表达，在大脑中表达水平较低，包括调节进食行为和葡萄糖感知的下丘脑神经元，在胰腺中的表达水平更低。胃饥饿素和胰岛素之间存在相互关系，这表明胃饥饿素调节葡萄糖稳态。敲除小鼠体内的胃饥饿素可增加葡萄糖诱导的胰岛素分泌，并改善外周胰岛素敏感性。本综述重点关注胃饥饿素在葡萄糖稳态中的新出现的作用，以及探讨胃饥饿素是否是糖尿病的潜在治疗靶点。
