Figure 1. Effects of estradiol on osteoblast maturation.

Primary rat osteoblasts isolated from neonatal calvarias were exposed to a combination of estradiol (10 nM) and the differentiation agent, including dexamethasone, ascorbic acid, and β-glycerophosphate, for 21 days. Control cells received the differentiation agent only. Cell morphology was observed using a light microscope (A). The symbol, →, indicates a calcified nodule. Alkaline phosphatase (ALP) activity was assayed with a colorimetric method (B). Mineralized nodules were stained using Alizarin red S- (C) and the von Kossa-staining (E) protocols. These nodule signals were quantified and statistically analyzed (D and F). Each value represent the mean ± SEM for n = 6. The symbol ^* indicates that the value significantly differed from the respective control group, p < 0.05. 100x.