雌激素和多巴胺对大鼠垂体组织中雌激素受体基因表达的影响

Effect of Estrogen and Dopamine on the Expression of Estrogen Receptor in Rat Pituitary Tissue

目的研究雌激素和多巴胺激动剂对雌激素受体在大鼠垂体组织表达的作用。方法20只成年雌性Wistar大鼠,切除卵巢后,随机分2组:(1)对照组(n=5),皮下植入空白硅胶管;(2)雌激素组(n=15)皮下植入含有乙烯雌酚的硅胶管,8周后,两组各处死5只大鼠,雌激素组剩余大鼠(n=10)取出硅胶管,随机再分2组,安慰剂组(n=5)给予自来水灌胃,多巴胺组(n=5)给予溴隐亭(多巴胺激动剂)灌胃,用药4周后处死动物。放免法测定血清PRL水平,用反转录-聚合酶链反应(RT-PCR)方法检测ERs在各组垂体组织中的表达,以-βactin作为内参照,借助于计算机凝胶成像系统分析表达量。结果ERα,ERβ以及TERP在各组大鼠垂体组织均有表达,其中ERα和TERP mRNA水平在雌激素组明显高于对照组(P<0.001),在安慰剂组和多巴胺组的表达无明显差别。结论大鼠垂体组织中存在ER的表达,雌激素对ERα和TERP的表达具有升调节作用,多巴胺不影响雌激素受体的表达。

Objective To examine the effect of estrogen and dopamine on the expression of estrogen receptor in the rat pituitary. Methods Ovariectomized Wistar rats were divided into two groups. Each rat in the estrogen group （n = 15） was subcutaneously implanted with an implant containing 20 mg diethylstilbestrol （DES）. Rats in the control group （n = 5 ） were implanted with blank implants. 4 weeks later, the rats of estrogen group were divided into 2 subgroups at random. Water was orally administrated to rats in the placebo group （n = 5）, dopamine agonist was orally administrated to rats in the dopamine group （n = 5 ）. At 4 weeks after treatment, all the rats were sacrificed. The expression of ERa, EPβ and TERP in the pituitary was detected by RT-PCR. Results ERa,ERβ and TERP were all expressed in the rat pituitary. ERa and TERP mRNA levels were significantly greater in the estrogen group than those in the control group （P 〈 0.001）. There were no significant differences in the levels of ERa and TERP mRNA between placebo group and dopamine group. Conclusion Estrogen has a stimulating effect on the expression of ERR and TERP, but no effect on the cxpression of ERα or TERP.