多巴胺和溴隐亭对体外垂体生长激素瘤细胞分泌生长激素的影响

Effect of Dopamine and Bromocriptine on Secretion of Growth Hormone by Pituitary Growth Hormone Secreting Tumor in Cell Culture

本实验研究多巴胺(DA)及其激动剂溴隐亭(CB154)对6例体外培养的垂体单纯生长激素(GH)分泌瘤GH分泌的调节作用,并与生长抑素类似物SMS_(201-995)(SMS)的作用进行比较。结果10^(-8)和10^(-7)mol/LDA仅使1例瘤细胞的GH分泌明显减少,分别下降到对照GH分泌量的50.6％和44.4％;而10^(-7)和10^(-6)mol/L CB154却能使4例瘤细胞中3例GH分泌明显减少,平均下降到59.0±8.9％,表明CB154抑制GH分泌的作用强于DA。10^(-6)mol/L CB154使GH分泌下降到63.3±13.8％,而10^(-7)mol/L SMS则可使GH分泌下降到45.5±13.1％,二者浓度相差10倍,提示SMS的抑制作用至少比CB154强10倍。CB154不但能抑制GH分泌,还能抑制GH合成;而SMS则主要抑制GH分泌,对GH合成无明显影响。以上结果提示DA和CB154可直接抑制部分单纯GH分泌瘤GH的分泌,其作用机理与SMS不完全相同。

This article reports the effect of dopamine (DA) and its agonist bromocriptine (CB 154) on the secretion of growth hormone (GH) by pure GH-secreting pituitary tumor in cell culture as well as a comparison of the effects of these dopaminergic drugs and SM S_(201-995) (SMS) DA of 10^(-8) and 10^(-7) mol/L reduced GH secretion to 50. 6 and 44.4％of the control, respectively, in 1 out of 6 tumors. CB 154 of 10^(-7) and 10^(-6)mol/L suppressed GHs ecretion to 59.0±8.9％ of the control in 3 out of 4 tumors. CB154 was at least 10 times less potent than SMS visa vis GH secretion. CB154 of 10^(-6)mol/L inhibited GHsecretion to 63.3±13.8％(n=4), but SM S of 10^(-7)mol/L induced GHsecretion to 45.5±13.1％(n=4), the concentration difference between CB154 and SMS was 10 times. CB154 suppressed not only GH secretion, but also GH synthesis in two tumor cell cultures. The major role of SMS in GH secretion wasinhibition. The results suggest that DA and CB 154 have direct inhibitory effects on GH secretion, at least in some pure pituitary GH secreting tumors. The activities of DA and CB154 are not entirely the same as that of SMS.