М. М. Marchenko, O. V. Ketsa

Yuriy Fedkovych Chernivtsi National University, Ukraine;
e-mail: ketsa80@mail.ru

Generation of superoxide anion-radical (O₂^•-) in reductase and oxygenase electron-transport chains in the liver monooxygenase system was investigated in tumor-bearing rats exposed to preliminary irradiation. Preliminary irradiation of rats (before transplantation of Guerin’s carcinoma) resulted in the increased generation of superoxide anion-radical by components of the liver monooxygenase system in the logarithmic phase of oncogenesis­.
It is shown that the increased NADPH-cytochrome P-450 reductase activity is accompanied with the intensification of superoxide anion-radical generation in liver microsomal fraction of preliminary radiation-exposed rats. At the same time the cytochrome P-450 hydroxylase activity in the microsomal fraction of tumor-bearing rats subjected to preliminary irradiation was decreased.

Keywords: cytochrome P-450, Guerin’s carcinoma, liver, microsomal fraction, monooxygenase system, NADPH­-cytochrome P-450 reductase, superoxide-anion-radical