Epidermal growth factor requirement for development of cultured mammary gland.

The mouse mammary gland in serum-free whole organ culture can be manipulated hormonally to undergo one complete physiological cycle consisting of lobuloalveolar development, functional differentiation and regression, mimicking processes that occur in vivo. A second cycle has not previously been achieved in vitro. The present study has identified a specific requirement for epidermal growth factor (EGF) in the morphological development of mammary lobuloalveoli, allowing two complete cycles of development and regression in culture.