The effect of low-level irradiation on the structural and functional organization of the
cytochrome part of the respiratory chain in
tumor carrier rats' liver is studied. The preliminary low-level irradiation leading to the mitochondrial
cytochrome a, b and c content reduction at the latent stage of Guerin's
carcinoma is shown. At the same time, the maximal reduction of the content of all liver
cytochromes is observed at the terminal stages of
oncogenesis. The content of cytochome c undergoes the most significant changes in the liver mitochondrial fracture. The possible mechanism of mitochondrial
haem-containing
cytochromes content reduction may be associated with the disorder of their formation caused by the heam synthesis inhibition found in our study. Simultaneously, the
cytochrome oxydase (key
enzyme of the
cytochrome part) activity inhibition is observed to be caused by preliminary low-level irradiation at the latent growth stage of Guerin's
carcinoma. The determined differences between irradiated and non-irradiated
tumor carrier groups allow us to come to the conclusion that low-level irradiation has an impact only at the initial stages of the aftereffect. At the following stages, the state of the
cytochrome part of the respiratory chain is defined by growth conditions of
tumor.