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目的 研究人工合成的生长激素释放剂GHRP 6对体外培养的人垂体生长激素腺瘤细胞GH分泌影响 ,并分析其可能的临床意义。方法 用原代细胞培养技术 ,观察了 6例垂体GH腺瘤细胞和 4例正常胚胎垂体细胞对GHRP 6、生长释放激素 (GH releasinghormone,GHRH)和生长抑素 (somatostatin ,SS)的体外分泌效应。 结果 GHRP 6对所有 6例GH腺瘤细胞GH分泌表现出明显的刺激效应 (P <0 0 1) ,但远不如正常垂体细胞敏感 ,但GH腺瘤细胞对持续的GHRP 6刺激反应时间延长。GHRH和SS仅对部分GH腺瘤细胞有作用 ,且SS不能完全阻断GHRP 6对于GH分泌的刺激效应。结论 GH腺瘤细胞对于体外GHRP 6持续刺激的异常反应 ,表明垂体GH腺瘤中可能存在GH释放剂受体 (GHS R)所固有的负反馈机制———“脱敏”机制的减弱 ,且与肿瘤发病机制有关
Objective To study the effect of GHRP 6, a synthetic growth hormone releasing hormone, on the GH secretion of human pituitary somatotrophs cultured in vitro and its possible clinical significance. Methods Primary cultured human cells were used to observe the in vitro secretion of GHRP 6, GH releasing hormone (GHRH) and somatostatin (SS) in 6 pituitary glandular adenoma cells and 4 normal pituitary gland cells . Results GHRP 6 showed a significant stimulatory effect on GH secretion (P <0.01), but far less than that of normal pituitary gland cells, but prolonged GHRP 6 stimulatory response was observed in GH adenoma cells. GHRH and SS have an effect on only part of GH adenoma cells, and SS can not completely block the stimulatory effect of GHRP 6 on GH secretion. Conclusions The abnormal response of GH adenocarcinoma cells to sustained stimulation of GHRP 6 in vitro suggests that there may be a negative feedback mechanism inherent in GHS R in pituitary GH adenomas - a weakening of the “desensitisation” mechanism and And tumor pathogenesis