摘要
本研究旨在探讨糖皮质激素代谢酶 11β 羟基类固醇脱氢酶Ⅰ型 ( 11β HSD1)和糖皮质激素受体(GR)在大鼠海马神经元内的共同分布及其意义。用免疫细胞化学方法研究显示 ,海马神经元内不仅存在 11β HSD1免疫反应物质 ,还存在GR免疫反应物质 ,而且 11β HSD1与GR共存于同一个海马神经元内。用Western印迹杂交和薄层层析 (TLC)方法研究表明 ,地塞米松 (DEX)可以促进 11β HSD1蛋白表达及其酶的活性。利用11β HSD1基因启动子区序列构建的以CAT酶为报告基因的pBLCAT6质粒转染PC12细胞 ,证实DEX能够促进CAT酶的表达。以上糖皮质激素的作用均可为GR受体阻断剂RU3 8486所阻断。结果提示 :糖皮质激素 (GC)与GR结合后 ,可以作用于与其共存的 11β HSD1基因启动子区 ,使 11β HSD1表达增加 ,从而使更多的GC代谢产物转化为有活性的GC。
This paper was designed to observe the colocalization of 11β-HSD1 and GR, and its significance in the rat hippocampus. Immunocytochemical dual-staining showed that not only 11β-HSD1 but also GR immunoreactive substances were present in the cultured rat hippocampal neurons. Moreover, they were colocalized in the same hippocampal neuron. Synthetic glucocorticoid dexamethasone (DEX) up-regulated the protein expression and activity of 11β-HSD1 in the cultured hippocampal neurons, as determined by Western blot and thin layer chromatography (TLC) respectively. The transfection of PC12 cells with the plasmid containing promoter sequence of 11β-HSD1 gene and the reporter gene of CAT enzyme was conducted. DEX up-regulated the reporter gene expression in the system described above. The up-regulation of 11β-HSD1 and reporter gene expression induced by DEX were both blocked by GR antagonist RU38486. Our study suggests that the colocalization of 11β-HSD1 and GR in the hippocampus may be implicated in the up-regulation of 11β-HSD1 expression by glucocorticoids combining to its promoter region, which in turn produces more biologically active glucocorticoids necessary for the binding of low affinity of GR.
出处
《生理学报》
CAS
CSCD
北大核心
2002年第6期473-478,共6页
Acta Physiologica Sinica
基金
ThisworkwassupportedbytheNationalBasicResearchProgram (G19990 5 40 0 0 )ofChina .
