【摘要】 目的探讨地塞米松和生长激素释放激素(GHRH)对大鼠胚胎垂体生长激素(GH)细胞分化的作用,为将来选择性细胞移植治疗生长激素缺乏症(GHD)奠定基础。方法利用免疫组织化学方法和放射免疫分析方法,在大鼠胚胎垂体组织的原代培养中,对糖皮质激素诱导GH细胞分化的最佳浓度、诱导GH细胞发生分化所需要的最短时间以及GHRH在大鼠胚胎垂体细胞分化中的作用进行实验研究。结果地塞米松诱导GH细胞分化的最佳浓度为50nmol/L(P<0.01)。体外培养的胚胎垂体细胞经地塞米松诱导16h,GH细胞开始分化,诱导48h,分化更明显,上清液中GH水平也明显增加(P<0.01);当GHRH的浓度达到10-7mol/L时,可以增强地塞米松对GH细胞的诱导分化作用,明显提高GH细胞的百分比和GH的分泌量(P<0.01)。结论地塞米松可以诱导生长激素前体细胞最终分化为具有功能活性的GH细胞,GHRH与地塞米松发挥协同作用,调节GH细胞的分化与GH分泌。更多还原

【Abstract】 Objective To study the effects of dexamethasone and growth hormone releasing hormone on fetal rat pituitary somatotroph differentiation. Methods Us ing immunocytochemical and radioimmunological techniques, the optimal concentra tion and time course of glucocorticoid induction of growth hormone(GH) cells in primary cultures of rat embryonic pituitary cells, the regulation of somatotroph differentiation and growth hormone secretion by corticosterone and GH-releasing hormone during embryonic development were experimentally studied. Results In primary culture of rat fetal somatotroph, the amount of somatotroph and GH secr etion depended on dexamethasone concentration reached an optimal value of 50 nmo l/L(P < 0.01). Dexamethasone increased the number of GH cells and GH secretion w ithin 16 h; at 48 h, dexamethasone further increased somatotrophs and GH secreti on. The combination of corticosterone and growth hormone releasing hormone(GHRH) was significantly more effective than corticosterone alone in inducing somatotr oph differentiation, but only the highest concentration (10-7 mol/L) of GHRH was tested (P < 0.01). Conclusions Glucocorticoids may function as a requisite sig nal for induction of the final stages of somatotroph differentiation from cells that are already committed to this lineage. Dexamethasone and GHRH can interact at specific stages of embryonic development to regulate somatotroph differentiat ion and GH secretion.更多还原