Primary culture of porcine mammary epithelial cells as a model system for evaluation of milk protein expression

Porcine mammary epithelial cells were isolated to culture on collagen gel f ollowed by gel floating treatment to evaluate differentiation under the cul ture conditions of serum-free medium, supplemented with combinations of ins ulin, hydrocortisone, and prolactin. After the culture period, the mammary cells attached to the collagen gels were recovered to observe expression of beta -casein, beta -lactoglobulin, and lactoferrin by reverse transcriptas e polymeric chain reaction method. Expression of beta -casein was observed in the presence of insulin, hydrocortisone, and prolactin whereas transcrip tion of beta -lactoglobulin and lactoferrin occured irrespective of hydroco rtisone and prolactin. Immunoblot analysis demonstrated synthesis and secre tion of lactoferrin in the fraction of recovered cells and the culture medi um.