Abstract
In order to provide a procedure for studying the mechanism of milk production or carcinogenesis of mammary cells, we attempted to culture mammary epithelial cells from goat milk, and estimated the optimal conditions for the culture system. Cell proliferation was accomplished satisfactorily by using Eagle's minimum essential medium supplemented with 30% fetal calf serum (FCS). However, favorable proliferation was not observed when less than 20% FCS was present. In the course of culture, the cells adhered to plastic dishes within 1 or 2 days after seeding and formed small colonies within 5 days. Such colonies continued to increase in size and made contact with neighboring colonies to form sheets within 10 to 20 days. The sheet-forming cells showed various types of cell morphology, including spindle-like, polygonal and stellate forms. At the 5th or 6th passage, the main proportion of the cell population was comprised of elongated cells and pleomorphic cells. Most of the cells were positive for antikeratin and antiactin antiserum. Electron microscopy of vertical sections of the cell sheet revealed that the cells had flat nuclei and extremely extended cytoplasm. They exhibited an apparent epithelial nature in that they were interconnected by interdigitations and possessed microvilli and desmosomes. Morphological features of differentiation of these cultured cells, such as production of casein granules or lipid droplets, were not observed in the present culture system.
