核受体(nuclear receptor, NR)超家族成员孕烷X受体(pregnane X receptor, PXR)是一个配体激活型转录因子，高表达于肝脏和肠组织，在其它某些组织器官中也存在表达。PXR与维甲酸X受体(retinoid X receptor, RXR)形成异源二聚体，在招募大量共活化因子后，与特异性DNA响应元件结合发挥转录调控功能。PXR是一个公认的外源物质感受器，因此，PXR最初被认为是一种调节药物代谢酶和转运体的NR。但目前已知PXR也是同等重要的内源物质受体。最近的研究显示PXR激活可以调节体内葡萄糖代谢、脂质代谢、类固醇内分泌稳态、胆酸和胆红素去毒化、骨矿物质平衡和免疫炎症反应等，本文就这几个方面对PXR作一个综述。
Role of pregnane X receptor (PXR) in endobiotic metabolism
LUAN Zhi-Lin, HUO Xiao-Xiao, GUAN You-Fei *, ZHANG Xiao-Yan
Advanced Institute for Medical Sciences, Dalian Medical University, Dalian 116044, China
As a member of the nuclear receptor superfamily, the pregnane X receptor (PXR) is a ligand-activated transcription factor. PXR is highly expressed in liver and intestinal tissues, and also found in other tissues and organs, such as stomach and kidney. After heterodimerization with retinoic acid X receptor (RXR), PXR recruits numerous co-activating factors, and binds to specific DNA response elements to perform transcriptional regulation of the downstream target genes. As an acknowledged receptor for xenobiotis, PXR was initially considered as a nuclear receptor regulating drug metabolizing enzymes and transporters. However, nowadays, PXR has also been recognized as an important endobiotic receptor. Recent studies have shown that PXR activation can regulate glucose metabolism, lipid metabolism, steroid endocrine homeostasis, detoxification of cholic acid and bilirubin, bone mineral balance, and immune inflammation in vivo. This review focuses on the role of PXR in metabolism of endogenous substances.
Key words: hypoxia; drug-metabolizing enzymes; transporters; modulating mechanism；