Figure 5: Age-related changes in the hepatic CBR1 and GSTA protein expression normalized to the amount of β-actin (a). Interindividual differences in protein expression of GST and CBR1 in rat liver (b). Cytosolic fractions (4 μg of protein/lane) of 6-week-old (J1–J6) and 21-month-old (S1–S6) rats were subjected to SDS-PAGE with subsequent immunoblotting. Blots were then reacted with rabbit polyclonal anti-CBR1 antibody or goat polyclonal anti-GSTA antibody. Protein bands were marked by corresponding secondary antibodies using a chemiluminescent detection with an alkaline phosphatase substrate. Protein expression was normalized to the amount of the loading control β-actin using mouse monoclonal anti-beta-actin antibody. GSTA = alpha-glutathione S-transferase; CBR1 = carbonyl reductase 1.