雌激素受体α在大鼠垂体的表达及其调控的初步探讨

THE EXPRESSION OF ESTROGEN RECEPTOR α IN PITUITARY OF RATS AND ITS REGULATION

目的 :观察雌激素受体α(ERα)免疫反应阳性细胞在大鼠垂体的分布 ,并初步探讨其调控因素。方法 :应用免疫组织化学和原代细胞培养方法结合图像分析。结果 :①正常大鼠垂体前叶和后叶有丰富的ERα阳性细胞 ,ERα在出生 3d即有表达 ,一月龄大鼠己达到成年大鼠水平 ;②卵巢切除大鼠ERα表达减少 ,补充雌激素后其表达有所增高 ,但仍末达到正常水平 ;③动情期大鼠垂体前叶ERα表达最高 ,动情后期逐渐减少 ,动情间期达最低值 ;④白细胞介素 2可促进ERα表达 ,但雌激素在离体情况下未能促进其表达 ;⑤Tamoxifen可能通过阻断ERα表达而导致垂体细胞死亡。结论 :ERα作为信号转导通路的重要环节 ,在垂体细胞应答。

Aim: In the present study the expression of estrogen receptor α (ERα) in pituitary of rats and its regulation was studied. Methods: Using immunohistochemistry and primarily serum free culture methods with a computerassisted image analyzer . Results :① ER α is present extensively in the anterior and posterior pituitary of rats. It occurs in the first 3 days after birth and there is no difference of expression between one month old rats and adults. ②ER α immunostaining decreases apparently after ovariectomy and increases substituted with estradiol which is still under normal level. ③There are rhythmical changes of ERα in the estrous cycle of female rats. The immunostaining of ERα is the most intensive during the estrous period and lessenes gradually till the weakest in the diestrous period.④IL2 (IOOμ /L)can enhance the expression of ERα in serum free culture whereas the estradiol can't raise the transcription of ER α in vitro. ⑤Tamoxifen (1 μmol/L ) can lead to cell death possibly by blocking the expression of ERα.Conclusion:As a key pathway of signal transduction ERα is critical in the response, growth and survival of pituitary cells.