CYP2D6 and hydrops fetalis: 65) applied an HF diet to CYP2D6 humanised transgenic (Tg-CYP2D6) mice. Tg-CYP2D6 mice were fed either with HF diet or control diet for 18 weeks. Mice in the HF diet group had higher body and liver weights compared with the mice under control diet. Hepatic mRNA levels of Cyp2d6 decreased slightly, but protein levels and activity did not differ between the diet groups. In addition to CYP2D6, the expression of other cytochrome P450 genes such as Cyp1a2 and Cyp2c37 was decreased in the HF diet group. The mRNA expression of Cyp2b10 and Cyp3a11 was higher in the HF diet group.