高浓度糖皮质激素对垂体-肾上腺轴的影响  

Effect of High Glucocorticoid on Pituitary-Adrenal Axis

作　　者：邓琼[1] 梁辉[1] 张建文[1] 朱婉蓉 杜野 应晶 DENG Qiong;LIANG Hui;ZHANG Jian-wen;ZHU Wan-rong;DU Ye;YING Jing(Affiliated People s Hospital of Longhua,Shenzhen,Southern Medical University,Shenzhen 518109,China)

机构地区：[1]南方医科大学附属深圳市龙华区人民医院

出　　处：《安徽师范大学学报（自然科学版）》2020年第1期58-63,共6页Journal of Anhui Normal University(Natural Science)

基　　金：国家自然科学基金项目(31800984);广东省自然科学基金项目(2016A030310071);深圳市科技创新项目(JCYJ20160428171238706);深圳市卫计委项目(201605017)

摘　　要：本项目研究糖皮质激素反馈对糖皮质激素快速抑制垂体细胞中CRH刺激引起的ACTH分泌的作用。来源于雄性大鼠的垂体前叶细胞,以无血清培养基灌注2h后,30pM CRH可诱导ACTH稳定分泌,只有应激水平的皮质酮(1μM)对ACTH的分泌产生延迟的抑制作用;以无血清培养基孵育6h后,基础水平的皮质酮(10nM)快速抑制ACTH的分泌。放射免疫化学法检测结果显示预孵育2h和6h的培养基中残留的皮质醇分别为19.3nM和7.2nM。蛋白免疫印迹结果显示,基础生理条件下,预孵育6h的细胞细胞膜蛋白和细胞核蛋白中GR含量比预孵育2h的细胞更低一些;并且皮质酮刺激诱导预孵育6h的细胞中GR向细胞膜转运,而预孵育2h的细胞在皮质酮刺激下细胞膜蛋白GR含量未见增加。皮质酮对ACTH分泌的抑制不被嘌呤霉素或放线菌素D阻断。这些数据表明垂体中糖皮质激素反馈的敏感性取决于皮质酮给药前细胞所处环境的激素浓度。This study examined the glucocorticoid feedback whereby the glucocorticoids inhibit on CRH-stimulated ACTH secretion in pituitary cells.Anterior pituitary cells were prepared from male rats and perifused with serum-free medium before fraction collection.Thirty picomoles CRH induced constant ACTH secretion.After 2h pre-incubation,only the stress level of corticosterone(1μM)was able to induce a delayed inhibition on ACTH secretion.After 6h pre-incubation,basal corticosterone(10nM)exerted a rapid inhibition of ACTH secretion.RIP assay showed 19.3nM and 7.2nM cortisol in the medium which cells were preincubated for 2h and 6h,respectively.GR content was faint in membrane and nuclear fraction in 6h group,compared with 2h pre-incubation group at basal condition.Corticosterone induced membrane GR trafficking in 6h group,and no increase found in 2h group.The inhibition of corticosterone on ACTH secretion after 6h pre-incubation was not blocked by puromycin or actinomycin D.These data suggested that the sensitivity of glucocorticoid feedback in pituitary was dependent on the steroid concentration before the corticosterone administration.This study has great significance in the regulation of HPA axis in the disorders caused by chronic stress and high circulation levels of glucocorticoid.It will be helpful for further clarification of the molecular mechanism of glucocorticoid feedback,and provide some references for the treatment of hypercortisolism,also named Cushing syndrome.

关 键 词：糖皮质激素 糖皮质激素受体 反馈 垂体 

分 类 号：R335[医药卫生—人体生理学]