中文摘要：

胆固醇是高等生物体不可或缺的一种脂质小分子，发挥着重要的生物学功能。生物体进化出一整套堪称完美的机制来调控胆固醇的代谢平衡。该文重点介绍了在胆固醇合成途径中的两个主要的负反馈调节途径：SREBP通路和HMGCR蛋白降解通路。

英文摘要：

Cholesterol is an essential lipid and plays pivotal roles in eukaryotic organisms. The cells have evolved elegant mechanisms to maintain the cholesterol homeostasis. This review focuses on SREBP pathway and sterol-regulated degradation of HMG-CoA reductase, two major mechanisms governing the negative feedback regulation of de novo cholesterol biosynthesis.