关键词：肾上腺髓质；嗜铬细胞；糖皮质激素；Ca2+；环核苷酸
摘要 目的 ： 研究一氧化氮(NO)和一氧化碳(CO)及其细胞内信使cGMP对培养的胎盘细胞促肾上腺皮质素释放素(CRH)分泌的调节作用。方法 ： 采用细胞培养技术观察体外培养的胎盘细胞分别给予NO和CO的供体或前体、NO合酶和血红素加氧酶的抑制剂以及鸟苷酸环化酶的抑制剂后，培养上清和细胞内CRH含量的变化。CRH含量的测定应用放射免疫分析技术。结果 ： NO供体硝普钠不仅可显著抑制CRH的基础分泌，还可抑制由KCl刺激所致的CRH的释放。NO合酶的抑制剂L-硝基-精氨酸甲酯和鸟苷酸环化酶抑制剂LY83583可逆转硝普钠对CRH分泌的抑制作用，还可促进CRH的基础分泌。CO前体Hemin和血红素加氧酶的抑制剂ZnPP9对CRH的基础分泌和KCl刺激引起的CRH的释放均无影响。结论 ： 外源性和内源性的NO均可抑制胎盘CRH的分泌。NO抑制胎盘CRH分泌的作用可能是由cGMP介导的。CO对胎盘CRH的分泌无影响。
中国图书资料分类法分类号 R714.12
The effects of nitric oxide and carbon monoxide on corticotropin
releasing hormone secretion from cultured placental cells
Ni Xin, Roger Smith (Department of Neurobiology, Department of Basic Medicine, Second Military Medical University, Shanghai, 200433)
Abstract Objective: To investigate the effects of nitric oxide(NO) and carbon monoxide(CO) on corticotropin releasing hormone (CRH) secretion from cultured placental cells. Methods: Changes of CRH contents in culture media were observed after cultured placental cells were treated with NO and CO donors or precursors, NO synthase (NOS) and heme oxygenase (HO) inhibitors and guanylate cyclase inhibitor, respectively. Measurement of CRH contents was performed by radioimmunoassay(RIA). Results: Sodium nitroprusside (SNP), NO donor, inhibited basal and KCl stimulated CRH secretion from cultured placental cells. This effect could be reversed by L-nitro-arginine methyl ester (L-NAME), a NOS inhibitor. L- NAME also increased basal CRH secretion. LY83583,a guanylate cyclase inhibitor, reversed SNP-induced suppression of CRH secretion and enhanced basal CRH secretion. However, CO precursor Hemin and HO inhibitor ZnPP9, did not affect basal and KCl-stimulated CRH secretion. Conclusion: Exogenous and endogenous NO could inhibit CRH secretion from placental cells. CO has no effect on CRH secretion from placental cells. The inhibitory effect of NO on CRH exocytosis may be mediated by cGMP.
Key words nitric oxide; carbon monoxide; corticotropin releasing hormone; placenta
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