Various tissue extracts (30 μg) were separated by 10% SDS-PAGE, and the membrane was blotted with Cyp26a1 antibody (GTX128730) diluted at 1:1000. The HRP-conjugated anti-rabbit IgG antibody (GTX213110-01) was used to detect the primary antibody, and the signal was developed with Trident ECL plus-Enhanced.