[Do endothelial cells participate in the biotransformation of cyclophosphamide?]

Investigations with cyclophosphamide were done to answer the question of participation of the endothelium in biotransformation of xenobiotics. Cyclophosphamide inhibits the proliferation of cultivated endothelial cells only in high concentrations. Also after induction of the cells by phenobarbital or 2,5-diphenoxazole no increased toxicity of cyclophosphamide was observed. Though the endothelium disposes of cytochrome-P-450-dependent aryl-4-monooxygenases it does not take part in biotransformation of cyclophosphamide apparently. Further possibilities of biotransformation by endothelial cells will be discussed.