[ 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.
[Objective] To detect the expression of liver growth hormone receptor gene （GHR） during the eady development of Kazak sheep and Xinjiang fine-wool sheep, and thus provide information for the research about the early growth and development of sheep. [ Method] With real-time quantitative PCR, the liver GHR 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. E Result] The liver GHR gene was highly expressed in 2 day-old sheep, but the expression level fell to the lowest point at 30 days old and then rose continuously; the change trend after 30 days old was positively correlated with the cumulative growth curves of sheep （ P 〈0.05） ; GHR mRNA level was lower in Kazak sheep than in Xinjiang fine-wool sheep during 2 -90 days old, but the difference was ex- tremely significant （P 〈0.01 ） only at 2 days old and 90 days old. [ Conclusion] The male Kazak sheep and Xinjiang fine-wool sheep have similar model of developmental changes of liver GHR mRNA and the differences are smaller between these two species; GHR gene may play an important role in the regulation of sheep growth.
[目的]探讨绵羊肌肉生长激素受体基因（GHR）在生长发育早期的表达。[方法]用real time PCR法对不同日龄雄性哈萨克羊和新疆细毛羊背最长肌GHRmRNA的表达进行定量分析。[结果]绵羊背最长肌GHRmRNA的表达随着日龄的增加先升后降,然后趋于水平,30日龄时最高。哈萨克羊的表达量在2~90日龄期间都极显著低于新疆细毛羊（P〈0.01）。[结论]日龄和品种对绵羊肌肉GHR基因表达均有较大影响。
