Sugino N, Telleria C M, Gibori G
Department of Physiology and Biophysics, University of Illinois at Chicago, 60612-7342, USA.
Endocrinology. 1997 Oct;138(10):4497-500. doi: 10.1210/endo.138.10.5572.
In this study, we investigated whether progesterone exerts an intraluteal action despite the lack of progesterone receptors (PR) in the rat corpus luteum and whether progesterone acts through the glucocorticoid receptor (GR) to enhance its own levels by down-regulating the expression of 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD). We first established that the corpus luteum constitutively expresses the GR throughout pregnancy and after parturition. We also generated a temperature sensitive SV-40 transformed luteal cell line (GG-CL) that expresses the GR and 20alpha-HSD but lacks the PR. Treatment with different doses of either progesterone or dexamethasone caused a dose-related decrease in 20alpha-HSD mRNA in both cultured corpora lutea and in the luteal cell line. RU486, a PR/GR antagonist, completely blocked both the progesterone and the dexamethasone mediated inhibition of 20alpha-HSD expression in GG-CL cells. In summary, this report provides the first evidence that despite the absence of the PR in the rat corpus luteum, progesterone can act through the GR to down-regulate the expression of 20alpha-HSD, an enzyme that catabolizes progesterone and reduces progesterone secretion by the corpus luteum.
在本研究中，我们调查了尽管大鼠黄体中缺乏孕酮受体（PR），孕酮是否仍发挥黄体内部作用，以及孕酮是否通过糖皮质激素受体（GR）发挥作用，通过下调20α-羟基类固醇脱氢酶（20α-HSD）的表达来提高其自身水平。我们首先确定，黄体在整个孕期和产后均组成性表达GR。我们还构建了一种温度敏感的SV-40转化黄体细胞系（GG-CL），该细胞系表达GR和20α-HSD，但缺乏PR。用不同剂量的孕酮或地塞米松处理，均可导致培养的黄体和黄体细胞系中20α-HSD mRNA呈剂量依赖性降低。PR/GR拮抗剂RU486完全阻断了孕酮和地塞米松对GG-CL细胞中20α-HSD表达的介导抑制作用。总之，本报告首次提供了证据，表明尽管大鼠黄体中不存在PR，但孕酮可通过GR发挥作用，下调20α-HSD的表达，该酶可分解孕酮并减少黄体的孕酮分泌。
