Repression of hepatic cytochrome P450 2D expression in mice during Babesia microti infection.

To examine the effect of Babesia infection on the level of the drug-metabolizing enzyme hepatic cytochrome P450 (CYP) 2D, we intraperitoneally inoculated Babesia microti into male ICR mice. CYP2D protein and CYP2D9 mRNA were significantly decreased at 12 days after infection with B. microti. The activity of bunitrolol 4-hydroxylase, which is catalyzed by CYP2D, was also significantly decreased. The mRNA levels of transcriptional regulators of CYP2D9, hepatocyte nuclear factor 4α and signal transducer and activator of transcription 5b, were markedly suppressed. These results suggest that Babesia infection represses CYP2D expression in the mouse liver. The decline in CYP2D-dependent drug metabolism might be involved in the incidence of adverse drug reactions in patients with babesiosis.