OXIDATIVE PHOSPHORYLATION AND ENERGY STATUS IN DOXORUBICIN-SENSITIVE AND DOXORUBICIN-RESISTANT GUERIN CARCINOMA
The indices of energy status and mitochondria oxidative phosphorylation in Guerin carcinoma with different sensitivity to doxorubicin were studied. ATP, ADP and AMP contents were estimated by thin-layer chromatography. The mitochondria oxidative phosphorylation indices were studied by the polarographic method with the covered combined platinum electrode. On the first stage of resistance development (after 5–8 courses of the treatment) the mitochondria oxygen consumption rate (in presence of succinate or glutamate) during phosphorylation of ADP in doxorubicin-resistant tumors was lower than in drug-sensitive tumors. On the second stage of resistance development (after 16–20 courses of the treatment) this index in drug-resistant tumors, on the contrary, was higher than in doxorubicin-sensitive tumors. The ATP/O ratio in mitochondria of all substrains of Guerin carcinoma was practically equal. The ATP level in doxorubicin-resistant tumors (stages I and II) was lower as compared with drug-sensitive variant. On the other hand the AMP level was higher in drug-resistant carcinomas (stages I and II) than in sensitive substrain.
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