Regulative effects of high dose of glucocorticoid on protein expression and mRNA transcription of corticotropin-releasing hormone in paraventricular hypothalamic nucleus / 中华创伤杂志

ABSTRACT

Objective To observe the regulative effect of high dose of glucocorticoid (GC) on protein synthesis and mRNA transcription of corticotropin-releasing hormone (CRH) in paraventricular hypothalamic nucleus (PVN) so to ascertain whether there exists difference upon effect of GC either at high dose or at normal dose. Methods A total of 60 Wistar rats were divided into five groups, ie, blank control group, 10 -6 mol/L dexamethasone (DEX) group, 10 -9 mol/L DEX group, 9 g/L saline group and group that was treated with 10 -4 mol/L RU486 first and then with 10 -6 mol/L DEX. The drugs were given through femoral vein. CRH protein expression was measured by means of immunohistochemistry and laser confocal scanning microscophy (LCSM); CRH mRNA transcription level was investigated by in situ hybridization. Results There appeared positive CRH mRNA granules in cytoplasm of PVN after administration with 10 -6 mol/L DEX for 20 minutes but could be seen positive fluorescent granules of CRH protein 30 minutes later, which was reversed at an in advance blockage of GR, as was free in 10 -9 mol/L DEX group, 9 g/L saline group and blank control group. Conclusions High dose of GC can up regulate CRH gene expression in PVN and differs much from the traditional effect of GC at normal dose, as may be due to that high dose of GC exerts effects depending on membrane glucocorticoid receptor but normal dose of GC dose via iGR.