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Colocalization of 11#beta#-hydroxysteroid dehydrogenase type I and glucocorticoid receptor and its significance in rat hippocampus

Wan Shunlun, Liao Maoyao, Hao Rusong, Li Zhaofeng, Sun Gang

Department of Physiology,The Second Military Medical University.Shanghai 200433

Abstract

This paper was designed to observe the colocalization of 11#beta#-HSD1 and GR, and its significance in the rat hippocampus. Immunocytochemical dual-staining showed that not only 11#beta#-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 11#beta#-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 11#betA#-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 11#beta#-HSD1 and reproter gene expression induced by DEX were both blocked by GR antagonist RU38486. Our study suggests that the colocalization of 11#beta#-HSD1 and GR in the hippocampus may be implicated in the up-regulation of 11#beta#-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.

Key words: 11#beta#-hydroxysteroid dehydrogenase type I;Glucocorticoid receptor;Hippocampus

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Citing This Article：

Wan Shunlun, Liao Maoyao, Hao Rusong, Li Zhaofeng, Sun Gang. Colocalization of 11#beta#-hydroxysteroid dehydrogenase type I and glucocorticoid receptor and its significance in rat hippocampus. Acta Physiol Sin 2002; 54 (6): (in Chinese with English abstract).