乳蛋白是构成牛奶营养品质的主要物质基础，乳蛋白含量是奶业核心竞争力的重要标志。神经内分泌因子对奶牛乳蛋白合成具有重要的调控作用。Ghrelin是一种具有多种生物学功能的神经内分泌因子。已有研究表明， Ghrelin能促进大鼠肌肉组织蛋白合成，而且可以调节反刍动物摄食和能量代谢，提示Ghrelin可能对乳蛋白合成过程中具有潜在调节作用。本项目拟利用Western blot、RT-PCR、ELISA、EMSA等技术，通过分析血液Ghrelin水平与奶牛乳蛋白含量的相关性，检测Ghrelin对乳腺上皮细胞氨基酸摄取能力、乳蛋白合成及相关信号分子的影响，并进行在体验证，从分子、细胞和整体水平上明确Ghrelin对奶牛乳蛋白合成的影响及机制。为深入认识奶牛乳蛋白合成的调控机理提供科学依据，为通过人工干预手段来提高牛奶营养品质奠定理论基础。

Low nutritional quality of cow's milk has increasingly become a severe challenge faced by the healthy development of dairy industry in China. Milk protein is the main substance to determine the nutritional quality of cow's milk. Cow's milk quality could be affected by many factors, where neuroendocrine factor plays an important regulatory role to protein contents in cow's milk. Ghrelin is a neuroendocrine factor with various biological functions. It is reported that ghrelin plays regulatory role to protein synthesis in rats muscle tissue, but the effects and molecular mechanism of ghrelin on protein synthesis of cow's milk have not yet been systematically studied. The project will use western blotting, real-time PCR, ELISA, EMSA and other methods to explore the relativity between the level of ghrelin and the contents of protein in cow's milk, study the influences and mechanism of ghrelin on protein synthesis-related genes expression in mammary epithelial cells, verify the impacts of exogenous ghrelin on protein synthesis of cow's milk so as to identify the effects and molecular mechanism of ghrelin on protein synthesis of cow's milk from molecular, cellular and overall levels. These results will provide scientific basis to further study the regulatory mechanism of protein synthesis of cow's milk and improve the nutritional quality of cow's milk.