一氧化氮抑制ghrelin诱导的生长激素腺瘤GH3细胞生长激素分泌和细胞增殖及其机制

Nitric oxide Mocks growth hormone secretion and cell proliferation induced by ghrelin in GH3 cells

目的 检测一氧化氮（NO）对ghrelin诱导的大鼠GH3细胞的生长激素（GH）分泌和细胞增殖的影响,探讨NO的作用机制.方法 首先应用ghrelin在不同浓度分别作用2 h 应用ghrelin在工作浓度1×10-7mol/L,分别作用不同时间,检测对GH3细胞GH分泌的影响 然后检测NO的供体（SNAP,1×10-5 mol/L）和NO合成酶的抑制剂（NAME,1×10-5mol/L）对ghrelin诱导的GH分泌和细胞增殖的影响 用酶联免疫吸附试验（ELISA）方法检测GH水平,噻唑蓝（MTT）比色法检测细胞增殖,Western免疫印迹法检测细胞内信号通路蛋白的活性变化.结果 ghrelin刺激GH3细胞分泌GH呈时间和浓度依赖性（P＜0.01）,ghrelin明显刺激GH3细胞的增殖（P＜0.05） SNAP可抑制基础的和ghrelin刺激的GH分泌（P＜0.01）,对细胞增殖也有明显影响（P＜0.01）,而NAME对GH的分泌和细胞增殖无影响 ghrelin可诱导细胞外信号调节激酶（ERK）的活化,SNAP可以抑制这种效应.结论 NO抑制ghrelin诱导GH3细胞GH分泌和细胞增殖,其机制可能阻断了ghrelin激活的ERK信号通路.

Objective To investigate the effects of ghrelin and nitric oxide （NO） on growth hormone （GH） secretion and cell proliferation in rat GH3 cells and explore the possible action mechanism of NO. Methods GH3 cells were incubated with ghrelin at different concentrations for 2 h or at the dose of 1 × 10-7 mol/L for different time points to investigate the effects of ghrelin on GH secretion. The effects of ghrelin on GH secretion and cell proliferation after SNAP （ 1 × 10-5 mol/L） and NAME （ 1 × 10-5 mol/L）treatment were determined. GH levels in the cells medium were tested by enzyme linked immunosorbent assay （ELISA） kit. The cell proliferation rate was measured by MTT and the expression of cells proteins were examined by Western blotting. Results Ghrelin induced GH secretion in both time- and dose-dependent manners （P 〈0. 01 ） and ghrelin induced cell proliferation （P 〈0. 05 ）. The stimulatory effects of ghrelin were reduced by SNAP （ P 〈0. 01 ） but not by NAME. SNAP could also inhibit the basal GH secretion and cell proliferation （ P 〈 0. 01 ）. Ghrelin activated extracellular signal-regulated kinase （ERK） signaling pathway, which was blocked by SNAP. Conclusion NO blocks growth hormone secretion and cell proliferation induced by ghrelin in GH3 cells via blocking ERK signaling pathway.