Effect of Transforming Growth Factor-beta (TGF-β) on Mammary Development

Mammary growth and development in heifers and cows is regulated by a complex interaction of multiple stimuli, including environmental, nutritional, and endocrine factors. The action of these various stimuli is mediated by a host of growth factors, including transforming growth factor-beta (TGF-β). TGF-β is a potent inhibitor of mammary epithelial cell growth and regulates extracellular matrix composition. TGF-β is expressed during bovine mammary development and its expression is particularly high at times of mammary growth and reorganization. The purpose of this paper is to review what we know about TGF-β and mammary growth and to explain how TGF-β affects the cell cycle in a normal epithelial cell line.