Fig. 5.
BMP-2-induced osteoblast differentiation and mineralization is decreased by E2 in primary osteoblastic cell cultures. (A) Osteocalcin levels in the medium and (B) mineralized matrix visualized following alizarin red staining (left panel) and quantified after extraction (right panel) of bone marrow– or calvaria-derived cells treated with BMP-2 (25 ng/mL), E2 (10−8 M), or E2 and BMP-2 in the presence of β-glycerophosphate for 18 days. (C) Alkaline phosphatase activity in parallel cultures of calvaria-derived osteoblasts from WT controls (ERα+/+) and ERαNERKI/− mice incubated with BMP-2 (25 ng/mL), E2 (10−8 M), or E2 and BMP-2 for 3 days. (D) Osteocalcin levels in the culture medium of same cells as in C treated as described for 10 days. *p < .05 versus BMP-2 alone. The same results were reproduced in a second experiment.