Norstedt G, Levinovitz A, Möller C, Eriksson L C, Andersson G
Center for Biotechnology, Karolinska Institutet, Huddinge University Hospital, Sweden.
Carcinogenesis. 1988 Feb;9(2):209-13. doi: 10.1093/carcin/9.2.209.
Insulin-like growth factor I (IGF-I) and IGF-II are peptides that presumably are required for normal fetal and postpubertal growth. The production of IGFs is developmentally regulated and the liver appears to be a major site of production. By analysing mRNA levels for IGF-I and IGF-II in the rat liver we have attempted to further study the expression of these growth factors during development and regeneration as well as during the course of hepatic carcinogenesis. Fetal livers are characterized by a high level of IGF-II mRNA and a low level of IGF-I mRNA, while in adult livers the opposite situations occur, i.e. a high level of IGF-I mRNA and a non-measurable level of IGF-II mRNA. During the course of experimentally induced hepatic cancer, IGF-I mRNA was consistently reduced and in a majority of cancers analysed (6/9) IGF-II mRNA was increased, i.e. a fetal type of IGF expression can be switched on in some experimentally induced hepatocellular carcinomas. The onset of IGF-II production during hepatic carcinogenesis appears to be a late phenomenon since liver nodules, preceding the development of hepatocellular cancer, were found not to contain IGF-II mRNA. Furthermore, during hepatic regeneration following partial hepatectomy no marked change in IGF-I or IGF-II mRNA levels was noted. The above results suggest that the fetal growth factor IGF-II could have a role in hepatic cancer.
胰岛素样生长因子I（IGF-I）和IGF-II是可能对正常胎儿和青春期后生长所必需的肽。IGF的产生受发育调控，肝脏似乎是主要的产生部位。通过分析大鼠肝脏中IGF-I和IGF-II的mRNA水平，我们试图进一步研究这些生长因子在发育、再生以及肝癌发生过程中的表达情况。胎儿肝脏的特征是IGF-II mRNA水平高而IGF-I mRNA水平低，而在成年肝脏中则相反，即IGF-I mRNA水平高而IGF-II mRNA水平不可测。在实验诱导的肝癌发生过程中，IGF-I mRNA持续降低，并且在大多数分析的癌症（6/9）中IGF-II mRNA增加，即在一些实验诱导的肝细胞癌中可以开启胎儿型IGF表达。肝癌发生过程中IGF-II产生的开始似乎是一个晚期现象，因为在肝细胞癌发生之前的肝结节中未发现含有IGF-II mRNA。此外，在部分肝切除后的肝再生过程中，未观察到IGF-I或IGF-II mRNA水平有明显变化。上述结果表明胎儿生长因子IGF-II可能在肝癌中起作用。
