Serrano J, Shuldiner A R, Roberts C T, LeRoith D, de Pablo F
Diabetes Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892.
Endocrinology. 1990 Sep;127(3):1547-9. doi: 10.1210/endo-127-3-1547.
A definition of the role of IGF-I in differentiation and development requires a detailed understanding of its expression and tissue-specific regulation in embryogenesis. Standard techniques for analysis of IGF-I gene expression are not sufficiently sensitive for studies in early embryos. We have used the highly sensitive polymerase chain reaction (PCR) to study IGF-I gene expression in whole chick embryos from the late blastula stage (E0 = laying) through the end of organogenesis (day 8), and in liver, brain and pancreas during mid-late embryogenesis and perinatally (hatching = day 21). Although at low levels in the blastoderm and gastrula, IGF-I mRNA was detectable in the whole embryo in all stages studied, with a tendency of the signal to increase with age during the first week of embryogenesis. In mid- and late embryogenesis, we easily detected IGF-I mRNA transcripts in pancreas and brain while the levels in the liver were barely detectable. Liver IGF-I mRNA increased markedly at the peak of postnatal growth (day 50). These studies suggest that while the major source of postnatal IGF-I may be the liver, extrahepatic tissues may be the predominant source of IGF-I during prenatal chicken development.
要定义胰岛素样生长因子-I（IGF-I）在分化和发育中的作用，需要详细了解其在胚胎发生过程中的表达及组织特异性调控。用于分析IGF-I基因表达的标准技术对早期胚胎研究的敏感性不足。我们运用高灵敏度的聚合酶链反应（PCR），研究了从囊胚晚期（E0 = 产蛋）至器官发生末期（第8天）的全鸡胚胎，以及胚胎中后期和围产期（孵化 = 第21天）肝脏、脑和胰腺中的IGF-I基因表达。尽管在胚盘和原肠胚中IGF-I mRNA水平较低，但在所研究的所有阶段的全胚胎中均可检测到，且在胚胎发生的第一周信号有随年龄增加的趋势。在胚胎中后期，我们很容易在胰腺和脑中检测到IGF-I mRNA转录本，而肝脏中的水平几乎检测不到。肝脏IGF-I mRNA在出生后生长高峰期（第50天）显著增加。这些研究表明，虽然出生后IGF-I的主要来源可能是肝脏，但在产前鸡的发育过程中，肝外组织可能是IGF-I的主要来源。
