摘要
作者以血浆糖皮质激素浓度固定的动物模型,研究了糖皮质激素对大鼠糖皮质激素受体(GR)mRNA的调节作用。以人GR cDNA为探针,采用分子杂交技术检测GR mRNA的大小和相对含量,结果显示,大鼠GR nlRNA大小约为7.0 kb;皮下注射氢化可的松后1 h肝GR mRNA无明显变化,6 h后开始明显减少,3 d后降至最低水平,仅为对照的44.0±5.0％,11 d后GR mRNA仍未完全恢复。与肝GRmRNA相比较,皮下注射氢化可的松后24 h大鼠脑GR mRNA变化并不明显。与以前用同种动物模型所得到的有关糖皮质激素对大鼠GR调节的资料相比较,提示糖皮质激素对GR的调节除发生于mRNA水平外,尚有其他机制参与,而且具有组织特异性特点。
The effect of glucocorticoids on the down-regulation of glucocorticoid receptor (GR) mRNA was studied in intact rats. GR mRNA was characterized by Northern blot hybridization and quantitated by dot blot hybridization using a human GR cDNA fragment as a probe. Administration of hydrocortisone in polyvinyl alcohol resulted in a rapid increase in plasma glucocorticoids which maintained at stress levels (20 to 40 μg/dl) for about 3 d. Hepatic GR mRNA decreased significantly to 73.5±63% of control values 6 h following hydrocortisone treatment, after which the decline of GR mRNA was gradual, reaching a minimum of 44.0±5.0% of control levels 3 d after the treatment The effect of hydrocortisone on the down-regulation of hepatic GR mRNA lasted up to 11 d. In contrast, hydrocortisone treatment had no effect on GR mRNA in rat brain. These results are consistent with the changes in GR in rats as reported previously, except that even though the hepatic cytosol GR decreased markedly, no significant changes in hepatic GR mRNA were found 1 h after hydrocortisone treatment, strongly suggesting that the down-regulation of GR by its ligands in vivo occurs at both transcriptional and posttranscriptional levels and is of tissue-specific fashion.
出处
《第二军医大学学报》
CAS
CSCD
北大核心
1990年第5期393-395,共3页
Academic Journal of Second Military Medical University
关键词
糖皮质激素
受体
MRNA
下降调节
glucocorticoid receptor, hydrocortisone
down-regulation
cDNA
mRNA
molecular hybridization
rats
