Ghrelin: the link connecting growth with metabolism and energy homeostasis.
Ghrelin: the link connecting growth with metabolism and energy homeostasis.
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DOI：
10.1023/a:1020901624103
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发表时间：
2002-12-01
影响因子：
8.2
通讯作者：
Dieguez, Carlos
中科院分区：
文献类型：
--
作者：
Casanueva, Felipe F;Dieguez, Carlos
生长激素（GH）是唯一受代谢环境严格调节的垂体激素，这种调节似乎叠加在肽类激素的经典调节之上[1]。此外，下丘脑对生长激素分泌的GH的调节也是独特的，因为它是通过GH释放激素（GHRH）的刺激作用和生长抑素的抑制作用来实现的。因此，生长激素是唯一已知的由两种拮抗性下丘脑激素调节的垂体激素，其他激素仅由一种神经激素控制。在外周，肝源性激素IGF-I的合成和血浆水平在很大程度上由GH刺激，对GH分泌施加经典的负反馈，通过作用于下丘脑和垂体水平来抑制GH分泌。其他外周激素，如甲状腺素，性腺类固醇，糖皮质激素和瘦素调节GH的确切数量，并以某种方式将生长激素状态与身体的整体激素平衡联系起来。最后，代谢信号，如葡萄糖、氨基酸和游离脂肪酸及其副产物，如酮酸，在GH分泌的控制中发挥相关作用，因此食物摄入是促生长素功能的调节事件[2]。这幅图的结果是一种激素，它的作用涉及对躯体生长和一般代谢的调节的双重作用，而这反过来又受到个体能量稳态的调节。目前，这种作用和调节的双重领域似乎可以用一种新发现的激素胃饥饿素来解释[3，4]。Ghrelin可能是连接躯体生长和体成分与一般代谢的桥梁。
Growth hormone (GH) is the sole pituitary hormone that is tightly regulated by the metabolic milieu, and this regulation appears to be superimposed over the classical regulation by peptide hormones [1]. Furthermore, the hypothalamic regulation of the GH secreted by the somatotroph is also peculiar, as it is exerted through the stimulatory action of GH releasing hormone (GHRH) and the inhibitory one of somatostatin. Thus, GH is the only known pituitary hormone regulated by two antagonistic hypothalamic hormones, the others being controlled by just one neurohormone. Peripherally, a liver-derived hormone, IGF-I, the synthesis and plasma levels of which are stimulated in great part by GH, exerts classical negative feedback on GH secretion, inhibiting it by acting both at hypothalamic and pituitary levels. Other peripheral hormones, such as thyroxine, gonadal steroids, glucocorticoids and leptin modulate the exact amount of GH and, in some way, connect the somatotroph status with the overall hormonal balance of the body. Finally, metabolic signals such as glucose, aminoacids, and free fatty acids and their by-products, such as keto-acids, exert a relevant role in the control of GH secretion, food intake is then a regulatory event of somatotroph function [2]. The upshot of this picture is of one hormone whose actions are implicated in a dual action on somatic growth and in the regulation of general metabolism, and which is, in turn, regulated by the energetic homeostasis of the individual. This dual field of action and regulation currently seems to be explained by a newly discovered hormone, ghrelin [3, 4]. Ghrelin may well be the bridge connecting somatic growth and body composition with general metabolism.