Glucocorticoid Regulation of Prolactin Receptors on Mammary Cells in Culture*

Abstract

Mouse mammary epithelial cultures were examined for the ability to specifically bind [¹²⁵I]PRL after cultivation on floating collagen gels. Corticosterone, particularly hydrocortisone, were effective in increasing the ability of mouse mammary cells to bind [¹²⁵I]PRL. The absence of a glucocorticoid in the medium resulted in a loss of PRL binding during the 3 days in culture. 17β-Estradiol, progesterone, and aldosterone at equal molar concentration had no or only a small effect in increasing [¹²⁵I]PRL binding.