Swolin D, Brantsing C, Matejka G, Ohlsson C
Department of Internal Medicine, University of Göteborg, Sweden.
J Endocrinol. 1996 Jun;149(3):397-403. doi: 10.1677/joe.0.1490397.
Excess levels of glucocorticoids are known to cause osteoporosis. It is speculated that the effect of glucocorticoids could be mediated via regulation of IGF-I. The aims of the present study were to detect and quantify the expression of IGF-I and/or IGF-II mRNA transcripts in human osteoblast-like cells and to investigate whether glucocorticoids regulate the expression of IGF-I mRNA transcripts in human osteoblast-like cells. Cultures of human osteoblast-like cells from trabecular bone were established. The IGF-IA and IGF-IB transcripts were detected in human osteoblast-like cells from seven out of nine patients while the IGF-II transcript was detected in human osteoblast-like cells from eight out of nine patients, as determined by RT-PCR assays. Human osteoblast-like cells, as well as human muscle tissue, expressed approximately 1/10 of the IGF-I mRNA levels found in liver, as determined by RNase protection solution hybridization assay. The IGF-I mRNA levels did not decrease with age in the human osteoblast-like cells and no difference was seen between males and females. However, cortisol (10(-6) mol/l) decreased IGF-I mRNA levels. In summary, the present study has shown that human osteoblast-like cells express IGF-I and IGF-II mRNA transcripts and that cortisol down-regulates the IGF-I mRNA levels, indicating that some of the inhibitory effect of glucocorticoids on bone formation in humans is mediated via a reduced autocrine/paracrine expression of IGF-I.
已知糖皮质激素水平过高会导致骨质疏松症。据推测，糖皮质激素的作用可能是通过调节胰岛素样生长因子-I（IGF-I）介导的。本研究的目的是检测并定量人成骨样细胞中IGF-I和/或IGF-II mRNA转录本的表达，并研究糖皮质激素是否调节人成骨样细胞中IGF-I mRNA转录本的表达。建立了来自小梁骨的人成骨样细胞培养物。通过逆转录-聚合酶链反应（RT-PCR）分析确定，在9名患者中的7名患者的人成骨样细胞中检测到了IGF-IA和IGF-IB转录本，而在9名患者中的8名患者的人成骨样细胞中检测到了IGF-II转录本。通过核糖核酸酶保护溶液杂交分析确定，人成骨样细胞以及人肌肉组织表达的IGF-I mRNA水平约为肝脏中发现水平的1/10。在人成骨样细胞中，IGF-I mRNA水平不会随年龄下降，男性和女性之间也没有差异。然而，皮质醇（10^(-6) mol/l）会降低IGF-I mRNA水平。总之，本研究表明人成骨样细胞表达IGF-I和IGF-II mRNA转录本，并且皮质醇会下调IGF-I mRNA水平，这表明糖皮质激素对人类骨形成的一些抑制作用是通过IGF-I自分泌/旁分泌表达减少介导的。
