绵羊肌肉IGF-I.基因表达的发育性变化研究

生长激素（GH）在动物体内主要有两种作用方式：（1）GH与肝脏等靶器官上的GHR结合，产生胰岛素样生长因子（IGF），随后IGF以内分泌方式进入血液，与胰岛素样生长因子结合蛋白（IGFBP）结合后到达靶器官，作用于胰岛素样生长因子受体（IGFR），从而调节动物生长发育。②GH直接作用于靶器官GHR，通过旁分泌或自分泌IGF直接影响细胞的代谢，从而调节机体的生长发育。GH可作用于骨骼肌GHR，产生旁分泌或自分泌的IGF-I调节肌肉的生长发育，或直接影响细胞的代谢。笔者采用实时定量PCR法，以处于生长发育早期的雄性哈萨克羊和雄性新疆细毛羊为研究对象，检测了IGF-I基因在肌肉中表达情况。

Developmental Changes of IGF-I mRNA Expression Level in Sheep Muscle

Objective] To detect the mRNA of muscle insulin-like growth factorl （IGF-I） in the early development of Kazak sheep and Xinjiang fine-wool sheep, so as to provide information for the research about the early growth and development of sheep. Method] With real-time quan- titative PCR, the muscle IGF-I mRNA level was separately detected in two varieties of sheep at 2, 30, 60, 90 and 120 days old. Then the data was analyzed with SPSS software. Result] The IGF-I mRNA in sheep muscle first increased and then decreased with ages, peaking at 30 days old in Kazak sheep and at 60 days old in Xinjiang fine-wool sheep. The IGF-I expression level of Kazak sheep had no significant difference with Xinjiang fine-wool sheep at 2 or 90 days old （ P 〉0.05）, but was lower than that of the latter with extremely significant difference （ P 〈0.01 ） from 30 to 60 days old. Conclusion] The male Kazak sheep and Xinjiang fine-wool sheep have similar model of developmental changes of muscular IGF-I mRNA, but the expression level is different between these two species.