Rao Ch V, Zhou X L, Lei Z M
Division of Research, Department of Obstetrics, Gynecology and Women's Health, University of Louisville Health Sciences Center, 438 MDR Building, 511 South Floyd Street, Louisville, KY 40292, USA.
Biol Reprod. 2004 Aug;71(2):579-87. doi: 10.1095/biolreprod.104.027300. Epub 2004 Apr 14.
Previous studies have suggested that activation of normal human adrenal and adrenal tumor luteinizing hormone (LH)/chorionic gonadotropin (hCG) receptors results in an increased secretion of steroid hormones. Since it is not feasible to test this suggestion on normal human adrenal cells, we used human adrenal cortical carcinoma H295R cells, which are similar in some respects to normal adrenal cortical cells. These cells contained LH/hCG receptor transcripts and receptor protein that can bind (125)I-hCG in a hormone-specific manner. Culturing the cells with highly purified hCG resulted in a time- and dose-dependent significant increase in dehydroepiandrosterone sulfate (DHEAS) secretion as compared with the controls. The DHEAS response was hormone as well as steroid specific. Since hCG treatment did not increase DHEA secretion, we suspected that the hCG might increase DHEA sulfotransferase (ST). Consistent with this possibility, hCG treatment increased steady-state DHEA-ST mRNA levels. The hCG effects require its receptors, as inhibition of their synthesis by treatment with antisense phosphorothioate oligodeoxynucleotides (ODN) made from the LH/hCG receptor sequence resulted in loss of DHEA-ST and DHEAS responses. The findings that 1) hCG treatment increased cAMP levels and activated protein kinase A (PKA), 2) 8-bromo cAMP mimicked hCG, and 3) blocking PKA activation prevented hCG as well as 8-bromo cAMP from increasing both DHEA-ST mRNA and DHEAS levels suggested that cAMP/PKA signaling was involved in the hCG actions. In conclusion, H295R cells contain LH/hCG receptors, which are coupled to increasing DHEAS secretion through upregulating the ST enzyme mRNA level. This action is mediated by the cAMP/PKA signaling pathway. These findings support the concept that adrenal function in normal and pathological conditions could be influenced by LH and hCG.
以往的研究表明，正常人类肾上腺及肾上腺肿瘤中的促黄体生成素（LH）/绒毛膜促性腺激素（hCG）受体激活会导致类固醇激素分泌增加。由于对正常人类肾上腺细胞进行该研究不可行，我们使用了人肾上腺皮质癌H295R细胞，这些细胞在某些方面与正常肾上腺皮质细胞相似。这些细胞含有LH/hCG受体转录本和能以激素特异性方式结合（125）I-hCG的受体蛋白。与对照组相比，用高度纯化的hCG培养这些细胞会导致硫酸脱氢表雄酮（DHEAS）分泌呈时间和剂量依赖性显著增加。DHEAS反应具有激素及类固醇特异性。由于hCG处理并未增加脱氢表雄酮（DHEA）分泌，我们怀疑hCG可能会增加硫酸脱氢表雄酮转移酶（ST）。与此可能性相符的是，hCG处理会增加DHEA-ST的稳态mRNA水平。hCG的作用需要其受体，因为用由LH/hCG受体序列制成的反义硫代磷酸酯寡脱氧核苷酸（ODN）处理来抑制其合成会导致DHEA-ST和DHEAS反应丧失。以下发现表明cAMP/PKA信号通路参与了hCG的作用：1）hCG处理会增加cAMP水平并激活蛋白激酶A（PKA）；2）8-溴cAMP模拟了hCG；3）阻断PKA激活可阻止hCG以及8-溴cAMP增加DHEA-ST mRNA和DHEAS水平。总之，H295R细胞含有LH/hCG受体，该受体通过上调ST酶的mRNA水平来增加DHEAS分泌。此作用由cAMP/PKA信号通路介导。这些发现支持了这样一种观点，即正常和病理状态下的肾上腺功能可能会受到LH和hCG的影响。
