Figure 2: Relative CYP1A2 mRNA, protein, and catalytic activity levels after 1, 3, 5, and 7 days of biotin treatment (2 mg/kg, i.p.). The data are expressed as fold changes relative to the control group (dashed line). The data represent the means ± SEM of 4 rats per group from two independent experiments. *Significantly different from the controls (), as assessed using Student’s t-test (a). Representative CYP1A2 immunoblot (24 hrs after biotin treatment). The intensities of the bands were normalized to GAPDH. The values are expressed as fold changes relative to the control group (dashed line). The (+) band corresponds to liver microsomes that were prepared from rats that had been treated with BaP (10 mg/kg), bands 2–5 are from control rats, and bands 6–9 correspond to biotin-treated rats (2 mg/kg). The molecular weights are indicated on the left: 54 kDa for CYP1A2 and 35 kDa for GAPDH. Four animals were used per group, and the data represent the results of two independent experiments (b).