Effect of Schistosoma mansoni infection on the hepatic drug-metabolizing capacity of mice.

Since infections with Schistosoma mansoni cause marked histopathological changes in the liver of the host, the effect of this infection on the hepatic drug-metabolizing function was investigated. Severity of Schistosomiasis was determined by worm counts, duration of infection, egg counts and liver weight increases. To overcome difficulties in homogenizing the livers of infected animals, preincubation of the squashed tissues with collagenase and hyaluronidase was used to prepare homogenates. Key component enzyme activities of the hepatic microsomal drug-metabolizing enzyme system (NADPH-cytochrome c reductase and cytochrome P-450) as well as the representative drug-metabolism activities (aminopyrine N-demethylase, aniline hydroxylase, and benzpyrene hydroxylase) were measured for the whole liver and found to be markedly reduced. However, the measurement of microsomal marker enzyme activities (cytochrome b5 and glucose-6-phosphatase) showed significant elevation. To obtain more precise information about the effect of the schistosome infection on the hepatic drug-metabolizing enzyme system, the total activities of microsomal drug-metabolizing enzymes were related to the total microsomal marker enzyme activities in the homogenate.