Koh Phil Ok, Kim Yoon Sook, Cheon Eun Woo, Kang Sang Soo, Cho Gyeong Jae, Choi Wan Sung
Department of Anatomy, College of Medicine, Gyeongsang National University, Jinju 660-751, Korea.
Mol Cells. 2002 Dec 31;14(3):355-60.
The production of a steroid hormone in the placenta is essential for maintaining the pregnancy and developing the fetus during gestation. In various steroidogenic tissues (including gonads and adrenal cortex), the steroidogenic-acute-regulatory protein (StAR) acutely transfers cholesterol from the outer to the inner mitochondrial membrane for rapid steroidogenesis. Although steroid hormones were synthesized in the rat placenta, the developmental expression of StAR has been poorly understood in the rat placenta during mid-late pregnancy. Therefore, the aim of the present study was to establish the expression and localization of StAR mRNA in the rat placenta during mid-late pregnancy using Northern blots and in situ hybridization. The Northern blot analysis showed that the StAR mRNA expression significantly changed as the gestation day (GD) progressed. The placental expression of StAR mRNA increased between GD 11 and 13, and then slightly decreased until term. In situ hybridization showed a strong StAR expression in giant trophoblast cells on GD 11 and 13, and a moderate expression in trophoblast and stroma cells within the villi of the labyrinth zone throughout the pregnancy. In this study, we reveal for the first time the existence of StAR mRNA in steroidogenic cells of the placenta during mid-late pregnancy. In conclusion, our results suggest that StAR may regulate steroidogenesis in the rat placenta to maintain the pregnancy and developing the fetus.
胎盘产生类固醇激素对于维持妊娠以及在妊娠期使胎儿发育至关重要。在各种类固醇生成组织（包括性腺和肾上腺皮质）中，类固醇生成急性调节蛋白（StAR）可将胆固醇从线粒体外膜迅速转运至内膜，以实现快速的类固醇生成。尽管大鼠胎盘能合成类固醇激素，但在妊娠中后期，大鼠胎盘内StAR的发育性表达情况却鲜为人知。因此，本研究的目的是利用Northern印迹法和原位杂交技术确定妊娠中后期大鼠胎盘内StAR mRNA的表达及定位。Northern印迹分析表明，随着妊娠天数（GD）的增加，StAR mRNA的表达发生了显著变化。StAR mRNA在胎盘的表达在GD 11至13之间增加，然后直至足月略有下降。原位杂交显示，在GD 11和13时，巨大滋养层细胞中有强烈的StAR表达，在整个妊娠期，迷路区绒毛内的滋养层和基质细胞中有中度表达。在本研究中，我们首次揭示了妊娠中后期胎盘类固醇生成细胞中存在StAR mRNA。总之，我们的结果表明，StAR可能调节大鼠胎盘内的类固醇生成，以维持妊娠并使胎儿发育。
