Alterations in the carcinogen metabolizing capacities of mouse-liver during schistosoma-mansoni infection.

Male Balb/c mice were infected with the cercariae larvae of Schistosoma mansoni and livers were taken for analyses at 15, 30, 45, 60 and 75 days post-infection. By comparison with age matched controls, changes were observed in liver weight, hepatic microsomal protein and enzymes of xenobiotic metabolism. Transitory increases were observed in the hepatic content of cytochromes P-450 and b5 and to a greater extent in the activity of arylhydrocarbon hydroxylase during S.mansoni infection. The expression of these activities reached its peak at 30 days post-infection with a steady impairment as the infection proceeds. This pattern of activity can indicate an increased capacity to generate active metabolites potentially capable of acting as preneoplastic initiating agents particularly in the early stages of infection. Accompanied changes in the profile of hepatic glutathione content over the similar time course may partly compensate for these effects. Also these changes may suggest a gradual but definite declination in the detoxification capacity of the infected livers at the late stages of schistosomiasis. These observations indicate that schistosome infection might potentiate the deleterious effects of environmental chemical carcinogens.