Fig. 1.

ERK phosphorylation in primary wild-type (WT) and estrogen receptor (ER)β-knockout (BERKO) calvarial cells. A: Western blot analysis of anti-ERK phosphorylation (p-ERK; Y site) and ERK in WT and BERKO cells exposed to static conditions (S) or 30 min of oscillatory fluid flow (OFF) (F) in the absence (VEH) and presence of estradiol (E₂). Representative bands from experimental groups are shown. Bands taken from noncontiguous lanes are divided by black lines. B: quantification of p-ERK/ERK densitometric ratios, normalized by the mean of p-ERK/ERK for the WT S VEH group (thus shown as “1”), is presented. Experimental groups contain 2–3 samples. Bars represent normalized means ± SE. Genotype, F, and E₂ were not significant factors by a 3-way ANOVA; however, WT + VEH F was significantly greater than WT + VEH S when compared using a Student t-test. ^aP < 0.05 vs. WT + VEH S.