Influence of antioxydants and phenobarbital on enzymes of metabolic activation of cyclophosphamide in rats

In experiment performed on 185 rats it has been shown that cyclophosphamide (CP) in a dose of 150 mg/kg after 7 days caused 1,5-3-fold decrease in the activities of amidopyrin-N-demethilase, erythromycin-N-demethilase, hexoba rbital-hydroxylase and CP-hydroxilase. CP also caused the inhibition of CP metabolism and decrease in the excretion of the active CP metabolites with urine. Implantation of Guerin's carcinoma decreased hepatic monooxygenase a ctivity. Tocopherol, retinol, selenum, phenobarbital, as well as the comple x of antioxidants and sorbent protected microsomal enzymes from inhibitory influence of the tumor and toxic CP metabolites. At the same time the excre tion of active CP metabolites restored.