地塞米松对大鼠再生肝鸟氨酸脱羧酶活性及其基因表达的影响

Effect of Dexamethasone on Ornithine Decarboxylase Activity and on Its Gene Expression in Regenerating Rat Liver

采用高效液相色谱和原位杂交技术研究了地塞米松对大鼠再生肝鸟氨酸脱羧酶(ODC)及ODCmRNA表达的影响.结果显示,大鼠完整肝脏中ODC水平较低,部分肝切除(PH)后2 h,不同处理组ODC活性开始升高,5 h达到最高值,其中:去肾上腺+NaCl组的酶活性高于对照组(去肾上腺假手术组),而去肾上腺+地塞米松处理组的酶活性低于对照组;24 h恢复到肝切除前水平.完整肝脏的ODC mRNA水平极低,PH后表达量迅速增加,5 h达到最大值,不同处理组mRNA水平的高低顺序与酶活性一致,12 h降至肝切除前水平.以上结果表明,在PH诱导的再生肝中,ODC mRNA表达量的增加或减少是造成ODC活性改变的原因之一,地塞米松对ODC活性及其mRNA的表达具有抑制作用,且主要表现在肝再生的早期.

The effect of dexamethasone on ornithine decarboxylase （ODC） activity and its mRNA expression of the regenerating liver in sham-operated and adrenalectomized male Sprague-Dawley rats were investigated using reverse-phage high--performance liquid chromatography and in situ hybridization assays. The results showed that ODC activities and mRNA levels which were low in intact livers increased rapidly in regenerating livers induced by partial hepatectomy （PH）, and commonly peaked 5 h after PH, and restored to the pre-PH levels at 24 h and 12 h, respectively, in all groups. The enzyme activities （at 5 h） and ODC mRNA levels （at 5 h） in adrenalectomized rats were higher than those of control （sham-adrenalectomized） rats. Meanwhile the lowest ODC activities and mRNA levels were detected in adrenalectomized rats treated with dexamethasone. These results suggested that the changes in the level of ODC mRNA expression contributed partly to the changes of ODC activity. ODC activity and ODC mRNA expression in regenerating liver induced by PH were inhibited by dexamethasone mainly in early stage of liver regeneration.