外源甲状腺激素对牙鲆IGF-I及其受体基因表达的影响

The Effects of Exogenous Thyroid Hormone on Gene Expression of IGF-I and IGF-IRs in Paralichthys olivaceus

采用外源的甲状腺激素(thyroid hormone,TH)分别处理变态前牙鲆仔鱼和体外培养的牙鲆胚胎细胞,通过实时定量PCR检测了TH处理前后牙鲆胰岛素样生长因子I(insulin-like growth factor I,IGF-I)及其受体(IGF-I receptors,IGF-IRs)基因的表达变化。在体和离体试验结果显示,过高浓度的TH会降低牙鲆仔鱼和胚胎细胞中IGF-I mRNA的表达,通过添加TH抑制剂硫脲(thiourea,TU)使仔鱼体内IGF-I mRNA上调;两种不同的IGF-IR对TH的响应是不同的,外源的TH能促进IGF-IR-1mRNA的表达,却使IGF-IR-2 mRNA的表达下调。结果表明在牙鲆的生长发育中TH和IGF系统是高度相关的。

In Paralichthys olivaceus, the gene expressions of insulin-like growth factor I （ IGF-I ） and its receptors after thyroid hormone （ TH ） treatment were analyzed using real-time quantitative PCR, by administration of TH to premetamorphic larvae and cultured embryonic ceils. The results in vivo and in vitro showed that the level of IGF-I mRNA dropped significantly after TH treatment, and it was up-regulated in thiourea （ TU ） treated premetamorphic larvae. The two IGF-IR mRNAs exhibited different expression patterns after TH treatment. The exogenous TH stimulated the expression of IGF-IR-1 mRNA, but obviously decreased the levels of IGF-IR-2 mRNA. These results reveal that TH and IGF systems are highly interrelated and provide the basic information to clarify the hormone regulation mechanisms of metamorphosis in Paralichthys olivaceus.