Impairment of hepatic cytochrome P-450-dependent monooxygenases by the malaria parasite Plasmodium berghei.

The effect of Plasmodium berghei infection on hepatic monooxygenase activities and cytochrome P-450 contents was investigated in mice. NIH/NMRI or A/J mice infected with active P. berghei showed 30-40% decreases in hepatic cytochrome P-450 contents and the ability to metabolize the test substrates, ethylmorphine and benzo(a)pyrene. These decreases were observed during the erythrocytic stage of the infection, but not during the initial exoerythrocytic stage, or after heat-inactivated sporozoites were injected. These results strongly suggest that malaria infections may significantly impair the capacity of the liver to metabolize drugs, carcinogens, and other foreign compounds.