[Effect of misonidazole (Ro 07-0582) and radiation on the monooxygenases of liver microsomes of the rat].

Three groups of male Wistar rats were compared: one group received injections of Misonidazole (MISO) (200 mg/kg, i.p.), another group was treated by whole-body irradiation, and the third population received both treatments. Irradiation induced an important decrease of monooxygenase (O-demethylase) activity of hepatic microsomes seven days after the treatment. Cyt. P-450 levels hardly decreased, whereas lipid peroxidation was two-fold three days after irradiation. These different parameters were not modified neither after misonidazole treatment nor after association of irradiation and MISO regimen. The presence of oxygen in liver may explain that a radiosensitizer such as MISO does not increase irradiation damage on liver microsomes enzymes, oxygen preventive activation of MISO by radiation: the nitro groupment of MISO was not reduced in nitroso and amine compounds.