Does the GH/IGF system mediate the effect of water temperature on fish growth? A review
Does the GH/IGF system mediate the effect of water temperature on fish growth? A review
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发表时间：
2005
期刊：
影响因子：
0.7
通讯作者：
J. Gabillard;C. Weil;P. Rescan;I. Navarro;J. Gutiérrez;P. Bail
中科院分区：
文献类型：
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作者：
J. Gabillard;C. Weil;P. Rescan;I. Navarro;J. Gutiérrez;P. Bail
和所有的变温动物一样，鱼类的生长强烈地依赖于水温。鉴于生长激素/IGF系统调节生长，它可能介导温度对鱼类生长的影响。事实上，在孵化前，虹鳟鱼在高温下的胚胎生长速度越快，整个胚胎中IGF2基因的表达就越高。此外，出生后的生长波动取决于水温，并与血浆GH和IGF1的变化有关。虽然季节参数，如光周期和营养状况也可以影响GH/IGF系统的活性，但已经表明，温度升高导致血浆GH的特异性增加。此外，血浆生长激素的增加导致血浆IGF1水平升高，并与生长速率相关。相比之下，血浆IGF2水平以及肌肉中IGF1和IGF2 mRNA的水平不受温度的特异性影响。因此，水温的季节性波动通过对血浆GH和IGF1水平的直接作用来影响生长速率。这种作用的机制尚未阐明，但可能源于代谢物水平的改变（葡萄糖、氨基酸、脂肪酸等），这些代谢产物通过胰腺或下丘脑的生长抑素直接或间接地调节生长激素的分泌。
In fish, as in all poikilotherms, growth is strongly dependent on water temperature. Given that the GH/IGF system regulates growth, it could mediate the effects of temperature on fish growth. Indeed, before hatching, the higher embryonic growth rate in rainbow trout at high temperatures is associated with higher expression of the IGF2 gene in the whole embryo. Furthermore, post-natal growth fluctuations depend on water temperature and are associated with variations of plasma GH and IGF1. Although seasonal parameters such as photoperiod and nutritional status can also affect GH/IGF system activity, it has been shown that an increased temperature led to a specific increase of plasma GH. Moreover, this increase of plasma GH leads to higher plasma IGF1 levels in correlation with the growth rate. By contrast, plasma IGF2 levels as well as muscular levels of IGF1 and IGF2 mRNA are not specifically modified by temperature. Thus, seasonal fluctuations of water temperature affect growth rate through a direct action on plasma GH and IGF1 levels. The mecha- nisms of this effect are not yet elucidated, but could arise from modifications of metabolite levels (glucose, amino acids, fatty acids, etc.), which regulate GH secretion directly or indirectly through somatostatin of pancreatic or hypothalamic origin.