ERK和Akt在地塞米松体外诱导胚胎期大鼠生长激素细胞分化中的作用  

Role of ERK and Akt indexamethasone-induced differentiation of embryonic rat somatotropes in vitro

作　　者：张宇[1] 吕文明[1] 杨光[1] 陶宇[1] 郑宏山[1] 项莹[2] 李国忠[1] 程玉[1] 

机构地区：[1]哈尔滨医科大学附属第一医院神经外科,哈尔滨150001 [2]哈尔滨医科大学附属第二医院内分泌与代谢科,哈尔滨150086

出　　处：《中国临床神经外科杂志》2014年第8期480-483,共4页Chinese Journal of Clinical Neurosurgery

摘　　要：目的探讨细胞外调节蛋白激酶(ERK)与蛋白激酶B(Akt)在地塞米松(Dex)诱导大鼠胚胎垂体生长激素(GH)细胞分化中的作用。方法原代培养大鼠胚胎垂体细胞48 h,加入Dex(50 nmol/L)进行诱导分化48 h,或加入Dex培养44 h后加入ERK抑制剂(10μmol/L)、Akt抑制剂(25μmol/L)或同时加入ERK抑制剂和Akt抑制剂进行培养4 h。利用免疫荧光染色计数GH阳性细胞百分比、免疫印迹法分析ERK和Akt磷酸化水平、放射免疫分析法检测细胞培养液GH含量和噻唑蓝比色法检测细胞增殖。结果 Dex显著增加GH阳性细胞百分比及细胞培养液GH含量(P<0.05),但其对垂体细胞增殖活性无显著影响(P>0.05)。在Dex诱导GH细胞分化过程中,抑制ERK或抑制Akt均能够显著降低GH阳性细胞百分比(P<0.05)和细胞培养液GH含量(P<0.05);与抑制ERK或抑制Akt相比,两者联合应用能进一步显著降低GH阳性细胞百分比及细胞培养液GH含量(P<0.05)。Akt抑制剂显著降低Akt的磷酸化水平(P<0.05),ERK抑制剂显著降低ERK的磷酸化水平(P<0.05)。结论 Dex可诱导大鼠胚胎垂体细胞向GH细胞分化,但不影响细胞增殖活性;ERK及Akt在Dex诱导GH细胞分化的过程中均发挥一定作用。Objective To study the effects of extracellular regulated protein kinases （ERK） and protein kinase B （PKB or Akt） on dexamethasone （Dex）-induced the differentiation of embryonic rat somatotropes in vitro. Methods The pituitary cells derived from embryonic rats were primarily cultured for 48 hours in the cuhure fluid without any reagents （control group）, and then they were continuously cultured again respectively in the culture fluid with Dex, Dex＋ERK inhibitor, Dex＋Akt inhibitor or Dex＋ERK inhibitor ＋ Akt inhibitor. The growth hormone （GH）-positive cells rate in the cultured pituitary cells and GH content in the supernatant of the culture fluid were determined respectively by immunoeytochimistry technique and radioimmunoassay. The proliferation rate of embryonic rat somatotropes was assessed by MTT assay. The levels of phospho-ERK and phospho-Akt were determined by western blotting. Results GH-positive cells rate, GH content and the levels of phospho-ERK and phospho-Akt were significantly higher in Dex group than those in the control group （P〈0.05）, but the proliferation rate did not change significantly between the two groups （P〉0.05）. GH-positive cells rate, GH content and the levels of phospho-ERK and phospho-Akt were significantly lower in Dex＋ERK inhibitor ＋ Akt inhibitor group than those both in Dex＋ERK inhibitor and Dex＋Akt inhibitor groups which were significantly lower than those in Dex group （P〈0.05）. Conclusions The embryonic rat pituitary cells can be induced into somatotropes by Dex which dose not change the proliferation rate of the somatotropes. Both ERK and Akt play an important role in the Dex-induced differentiation of embryonic rat somatotropes.

关 键 词：生长激素细胞 分化 地塞米松 细胞外调节蛋白激酶 蛋白激酶B 

分 类 号：R329.28[医药卫生—人体解剖和组织胚胎学]