Characterization of Differentiation of

2 In American society, dairy products are vital for nutrition and the economy. Optimizing the process of producing milk can benefit the consumers, producers, and the animals involved. Understanding the mechanisms of the development of the mammary gland can increase the efficiency of milk production, as well as improve animal health. Mammary epithelial cells (MEC) are the functional unit of the mammary gland. Although, there is a well-established MEC cell line, known as MAC-T, the use of a primary cell line is preferred because it more closely mimics an in vivo model. To better understand how mammary cell differentiation is regulated, it is vital to understand key mechanisms involved. One of the key genes involved in differentiation of MEC is the casein gene, which is expressed during mammary development and can be used to indicate differentiation of MEC. The main goal of this research is to establish the optimal methods for differentiation of primary bovine MEC in culture. Previous studies suggest that growth hormone (GH), also known as bovine somatotropin, is a promoter of MEC differentiation. Therefore, we hypothesize that GH will promote differentiation in MEC i