卵巢颗粒细胞中胰岛素和雄激素对芳香化酶和5α-还原酶1影响的研究

目的研究卵巢颗粒细胞中胰岛素对睾酮激素转化过程的影响。方法选用人卵巢颗粒细胞瘤样细胞系(KGN)作为研究对象。应用RT-PCR分析KGN细胞在梯度睾酮(1.25、2.5、5、10、20ng/ml)及胰岛素(1、10、100ng/ml)处理4h后CYP19a1和5RD5A1mRNA水平;Western-blot检测高浓度睾酮(10、20ng/ml)及梯度胰岛素处理KGN细胞24h后芳香化酶和5α-还原酶1蛋白水平;同步收集上清,应用放射性免疫法及酶联免疫法检测培养液上清睾酮、雌二醇及双氢睾酮的浓度。结果胰岛素剂量依赖性地上调CYP19a1的表达和活性,增加睾酮向雌二醇的转化;同时抑制5RD5A1的表达和活性,抑制睾酮向双氢睾酮的转化;转化比例改变但消耗水平不变,导致睾酮的异常累积。结论高雄激素环境下,胰岛素可通过影响睾酮转化酶促使睾酮转化异常。本实验为高胰岛素及高雄激素水平在卵巢微环境相互作用加剧PCOS病程提出了可能的机制。     

Modulation of expression of 17-Hydroxylase/17,20 lyase (CYP17) and P450 aromatase (CYP19) by inhibition of MEK1 in a human ovarian granulosa-like tumor cell line

The differential steroid production in the theca and granulosa cells in ovary are resulted from unique enzyme expression profiles. Among them, c-fos, a downstream target of mitogen and extracellular signal-regulated kinases (MEK/ERK) signaling, takes part in this compartment. In this study, we investigated the effect of c-fos on the steady-state levels of CYP17 and CYP19 in human ovarian granulosa-like tumor cell line (KGN) by inhibiting MEK/ERK pathway with PD98059. As a result, our finding demonstrated the distinct distribution patterns of CYP17 and CYP19 in KGN. Moreover, the MEK/ERK pathway functions to inhibit the production of CYP17, while enhance the production of CYP19 in granulosa cells, probably involving a c-fos-dependent mechanism. In conclusion, factors such as c-fos may play a crucial role in the down-regulation of CYP17 and up-regulation of CYP19 in granulosa cells, thereby suppressing androstenedione synthesis.     

A novel nonradioactive method for measuring aromatase activity using a human ovarian granulosa-like tumor cell line and an estrone ELISA.

Aromatase is a key enzyme in steroidogenesis and plays an important role in sexual differentiation, fertility, and carcinogenesis. Importantly, a variety of chemicals in the environment may influence its activity and thereby disrupt endocrine function. In the current studies, we developed a novel nonradioactive method for measuring aromatase activity that uses a specific ELISA for estrone along with KGN human ovary granulosa-like carcinoma cells. This cell line has relatively high aromatase activity, and because it lacks 17alpha-hydroxylase, it secretes little or no androstenedione, 17beta-estradiol, or estrone. Therefore, aromatase activity can be assayed simply by measuring the production of estrone in the culture medium after addition of the substrate, androstenedione. Furthermore, by making a slight change in the commercial ELISA kit and optimizing the experimental conditions, we developed a sensitive aromatase assay that could measure a wide range of estrone concentrations with very low interference by androgens. We used this assay to investigate the effects of 23 chemicals that have been previously reported to affect aromatase activity in vitro. We confirmed that 17 of 23 test chemicals had inhibitory or inducible effects, although the specific effects of some were different than previously reported. In conclusion, we have developed a simple, sensitive, and nonradioactive assay that can be used for large-scale screening of compounds that can disrupt endocrine function by influencing aromatase activity.     

GnRH拮抗剂联合来曲唑和米非司酮对体外培养的人颗粒细胞功能的影响

目的探讨促性腺激素释放激素拮抗剂(GnRH-ant)联合来曲唑和米非司酮对体外培养的人卵巢颗粒细胞功能及血管内皮生长因子(VEGF)表达的影响。方法体外培养人原代卵巢颗粒细胞及人卵巢颗粒细胞系KGN,根据所用药物不同分为GnRH-ant、来曲唑、米非司酮以及上述三种药物联合用药组,药物干预后检测细胞活力、细胞凋亡、培养液中雌二醇(E 2)及孕酮(P)水平及VEGF的表达。结果(1)GnRH-ant、来曲唑、米非司酮三种药物均可以不同程度地抑制原代颗粒细胞和KGN细胞的活力、促进颗粒细胞凋亡,其中联合用药组的作用最强(P<0.05);(2)GnRH-ant、来曲唑、米非司酮三种药物均可以不同程度地抑制原代颗粒细胞和KGN细胞E 2、P分泌水平,其中联合用药组E 2、P水平最低且差异有统计学意义(P<0.05);(3)GnRH-ant、来曲唑、米非司酮三种药物均可以不同程度地抑制原代颗粒细胞和KGN细胞VEGF表达,其中联合用药组VEGF mRNA及蛋白表达水平最低(P<0.05)。结论GnRH-ant联合来曲唑和米非司酮可以有效地抑制颗粒细胞活力、减少类固醇激素分泌及降低VEGF的表达水平。