溴隐亭对大鼠泌乳素瘤表达Pit-1的影响

 目的 研究溴隐亭对大鼠泌乳素瘤表达Pit-1的作用。方法 皮下植入17β-雌二醇制备大鼠泌乳素瘤模型,将成年雌性大鼠随机分为2组,正常对照组植入空白硅胶管,17β-雌二醇组植入装有17β-雌二醇的硅胶管;将成功诱发出泌乳素瘤的17β-雌二醇大鼠随机分2组,分为模型组、溴隐亭组(0.225 mg·kg^-1·d^-1),用药4周后处死动物,垂体称重,用放免法测定血清泌乳素水平,用反转录聚合酶链反应方法分析组织垂体Pit-1的表达水平。结果 17β-雌二醇组大鼠血清泌乳素水平和垂体质量均明显高于正常对照组（P<0.001）,组织学及免疫组化观察证实17β-雌二醇组成功诱发出大鼠泌乳素瘤。溴隐亭组Pit-1 mRNA水平、血清泌乳素水平和垂体质量低于模型组（P<0.001）。结论 17β-雌二醇成功诱发出大鼠泌乳素瘤,溴隐亭具有抗高泌乳素血症和抑制泌乳素瘤生长的作用,降低Pit-1的表达水平可能是溴隐亭抗泌乳素瘤的重要机制之一。

Effect of Bromocriptine on the Expression of Pit-1 in Prolactinoma Rats

OBJECTIVE To investigate the effect of bromocriptine on the expression of Pit-1 in prolactinoma rats. METHODS Firstly, to prepare prolactinoma model in rats. Adult Wistar rats were divided into two groups at random. The rats in control group were subscutaneously implanted with a blank implant. Rats in 17β-estradiol group were implanted with 17β-estradiol-containing implants. Secondly, rates in 17β-estradiol group were divided into two groups at randommodel group and bromocriptine group. Water was administrated to rats in model group. Bromocriptine (0.225 mg·kg^-1·d^-1) were orally administrated to rats in bromocriptine group, the rats in control group were orally administrated with water. After four weeks of treatment, all the animals were executed. Each pituitary gland was weighed. Serum prolactin(PRL) levels were measured by RIA method. Pit-1 mRNA levels in pituitary tissue were measured by RT-PCR method. RESULTS The weights of pituitary gland and PRL levels in 17β-estradiol group were individually higher than those in control group (P<0.001). The expression levels of Pit-1 mRNA in bromocriptine group was obviously lower than that in model group (P<0.001). CONCLUSION Bromocriptine has potential preventive effect to estrogen-induced rat prolactinoma. The decrease of Pit-1 mRNA level may be involved in the mechanism of anti-prolactinoma effect of bromocriptine.