Abstract
The influence of Schistosoma mansoni infection on the capacity of the carcinogen-metabolizing enzymes was investigated prior to and after treatment of the infected male mice with praziquantel, an anti-schistosomal agent. The drug was administered in a daily dose of 60 mg/kg body weight for three days before decapitation at various infection intervals. After 20 and 30 days post-infection the hepatic content of cytochrome P-450 and cytochrome b-5 and the activity of aryl hydrocarbon hydroxylase were markedly increased. However, the constitutive levels of the above mentioned enzymes were significantly decreased at 45, 60 and 75 days post-infection. Treatment of the infected mice with praziquantel for three days, however, recovered the changes in these activities at each individual time point. Praziquantel showed no effect on either of the studied enzymes when administered alone except for that of NADPH-cytochrome C reductase activity which exhibited significant increase. The activity of NADPH-cytochrome C reductase gave inconsistent results after treatment of the infected animals with praziquantel. It is concluded that praziquantel can be considered as a safe and useful drug for the chemotherapy of schistosomiasis and it possessed a recovery for the activities of the drug-metabolizing enzyme.