Figure 1.

Time course of CYP1A1 and CYP1B1 mRNA and protein expression under shear stress. Human umbilical vein endothelial cells were exposed to 0 (static), 1, 2, 4, 8, 24, 48, or 72 h of 25 dynes/cm² steady shear stress (n = 3–8). Both CYP1A1 (A) and CYP1B1 (B) mRNA were maximally induced by 24–72 h of shear stress. CYP1A1 protein (C) was usually detected only after 24 h of shear stress. CYP1B1 (D and E) protein was maximally induced after 24 h. Equal loading in (C) and (D) is indicated by reblotting the membranes with a β-actin antibody. Fold changes are relative to static values. Significance was assessed using analysis of variance followed by Tukey's post hoc test. *P < 0.05 vs. 0–8 h shear stress, ^‡P < 0.05 vs. indicated durations, ^#P < 0.05 vs. 0–8 h shear stress.