Fig. 2. IGFBPs are secreted from the basal surface of primary mammary epithelial cells grown on basement membrane. Cells were cultured on reconstituted basement membrane for 6 days in differentiation medium. Medium was replaced with serum-free medium (CON) or serum-free medium containing 2.5 mM EGTA for 10 minutes. Medium was then removed and concentrated before ligand blot analysis to detect IGFBPs and immunoblotting to detect secreted ß-casein. IGFBPs could not be detected in the basement membrane gel in the absence of cells (BM alone). Casein immunoblots and ligand blots are representative of three separate experiments.

Return to article