Figure 1

The effect of progestin (R5020) and extracellular matrix proteins on mammary epithelial DNA synthesis. Epithelial cells derived from nulliparous or pregnant mice were plated on poly-L-lysine (PL), collagen I (Col I), fibronectin (FN), tenascin (TN), laminin (LN), or collagen IV (Col IV) in serum-free medium. At 24 hour post-plating, the media was changed to either the control media or a media containing R5020 (20 nM). ³H-thymidine incorporation into DNA was determined 48 hour later. The percent increase was obtained by dividing counts per min/mg DNA of cells cultured in the presence of R5020 by counts per min/mg DNA of cells cultured in the absence of R5020. ^* P < 0.05 that R5020 stimulated proliferation of nulliparous derived cells on FN and Col IV. (Adapted from [3] with permission from Endocrinology).