Al-Massadi O, Trujillo M L, Señaris R, Pardo M, Castelao C, Casanueva F F, Seoane L M
Group of Fisiología Neuroendocrina, Lab 3, Instituto de Investigaciones Sanitarias (IDIS), Planta-2, Complejo Hospitalario Universitario de Santiago (CHUS), SERGAS, Travesía da Choupana, s/n, 15706 Santiago de Compostela, Spain.
Regul Pept. 2011 Jan 17;166(1-3):3-8. doi: 10.1016/j.regpep.2010.10.008. Epub 2010 Nov 5.
The growth hormone (GH) axis is mainly regulated by the growth hormone releasing hormone (GHRH) and somatostatin (SS) hypothalamic peptides. Nevertheless, since ghrelin peptide was discovered as the natural ligand for growth hormone secretagogue receptor (GHS-R), the mechanism of GH regulation has acquired a new dimension. It was described that ghrelin possesses a relevant effect inducing GH secretion when it is administered peripherally. A role of the vagus nerve mediating ghrelin action has been described although this effect is not understood. Under this context the main objective of this work was to determine the possible involvement of the vagus in the somatotroph axis regulation. The results in this manuscript show that animals with a disruption of the vagus connection presented lower basal IGF-1 and GH levels, a decreased GH response to peripheral GHRH administration and a marked diminution in the GH response to peripheral and central ghrelin treatments. In addition, vagotomized animals showed a down-regulation of GHRH mRNA in the arcuate nucleus of the hypothalamus and a down-regulation in both GHRH and GHS receptors' mRNA at the pituitary level. In conclusion, the present work reveals that the vagus nerve is crucial in growth hormone regulation and essential for the full GH-releasing effect of ghrelin.
生长激素（GH）轴主要受生长激素释放激素（GHRH）和下丘脑肽类生长抑素（SS）的调节。然而，自从胃饥饿素肽被发现是生长激素促分泌素受体（GHS-R）的天然配体以来，GH调节机制有了新的层面。有描述称，胃饥饿素经外周给药时具有诱导GH分泌的相关作用。虽然这种作用尚不清楚，但已有文献报道迷走神经在介导胃饥饿素作用中发挥作用。在此背景下，本研究的主要目的是确定迷走神经在生长激素轴调节中可能的参与情况。本论文中的结果表明，迷走神经连接中断的动物基础IGF-1和GH水平较低，对外周给予GHRH的GH反应降低，对外周和中枢给予胃饥饿素治疗的GH反应显著减弱。此外，迷走神经切断的动物下丘脑弓状核中GHRH mRNA下调，垂体水平的GHRH和GHS受体mRNA均下调。总之，本研究表明迷走神经在生长激素调节中至关重要，对胃饥饿素的完全GH释放作用必不可少。
