中文摘要：

乳脂肪含量与组成是构成牛奶重要营养品质的主要物质基础之一。牛乳脂肪的主要成分是甘油三酯，乳腺细胞以细胞内合成和胞外摄取两种形式获得脂肪酸并进一步合成甘油三酯。哺乳动物雷帕霉素靶蛋白（mammalian target of rapamycin，mTOR）是一个进化上十分保守的蛋白激酶，与其他蛋白一起组成mTOR信号通路，通过感受细胞内外的营养状况进而调控细胞生长和代谢，在乳脂合成中发挥重要作用。综述了mTOR信号通路在乳脂合成中的作用与机制，并结合研究现状展望了未来研究热点。

英文摘要：

Fat content and composition is one of the main substance constitutes of cow＇s milk, and triacylglycerol （TAG） is the main component. There are two sources of fatty acids in mammary epithelial cells for synthesizing TAG, i.e. intracellular synthesis and uptake from outside, roTOR （mammalian target of rapamycin）, a highly conserved kinase in evolution, composes mTOg signaling pathway with other proteins, regulates cell growth and metabolism by feeling the nutritional status in intracellular and extracellular environment, and plays a key role in milk fat synthesis. The role and mechanism of mTOR signaling pathway in milk fat synthesis were reviewed, and future research fields were discussed based on the current research.