[Xanthine oxidase activity in the rat liver tissue in the process of oncogenesis].

The work is dedicated to the investigation of xanthine oxidase activity in liver homogenate of rats with tumour at different stages of Guerin carcinoma oncogenesis on the preliminary low-dose irradiation background. Special attention is paid to studying enzyme oxidase form activity, the level of its reactive oxygen species generation and content of thiol groups in protein fraction, which possesses xanthine oxidase activity. The period of Guerin carcinoma active growth is characterized by the increase of total xanthine oxidase activity in the liver. It was found that oxidase activity and the level of O2* generation increase in the preliminary irradiated organism in the period of Guerin carcinoma active growth, as a result of enzyme SH-groups oxidation. At the terminal stages of oncogenesis the decrease of xanthine oxidase activity is accompanied by degradation of the molecule protein part.