A model for in vitro proliferation of undifferentiated bovine mammary epithelial cells

A method for culturing bovine undifferentiated mammary epithelial cells embedded in collagen gels is described. Cell growth was quantitated by incorporation of tritiated thymidine. Maximal rate of incorporation was achieved in media supplemented with sera, however considerable growth was observed in serum-free medium supplemented with insulin, transferrin and selenium. The growth promoting effect of insulin was maximally expressed only at high nonphysiological concentrations.