INTENSITY OF OXIDIZING AND REDUCING PROCESSES IN THE OXYGENASE AND REDUCTASE CHAINS OF THE MONOOXYGENASE SYSTEM OF RATS LIVER UNDER THE ACTION OF DIETHYLPHTALATE

The paper investigated the effect of different doses of diethyl phthalate (DEF) on the functional state of the components of the oxygenase and reductase chains of the monooxygenase system (MOS) in the microsomal fraction of the liver. The aim of the work was to evaluate redox transformations of cytochrome P450 (CYP) and cytochrome b5 in the microsomal fraction of rat liver under the influence of different doses of DEF. For the study, white outbred rats weighing 120-160 g were used, which were kept on a nutritionally balanced diet with free access to water. Experimental animals were divided into three groups: Group I - control (intact animals); II group – rats that were injected with DEF at a dose of 2.5 mg/kg of animal body weight; Group III - rats that were injected with DEF at a dose of 5.4 mg/kg of animal body weight. The rate of reduction-oxidation of CYP and cytochrome b5 was determined in the liver microsomal fraction. It was established that under the conditions of administration of DEF at a dose of 5.4 mg/kg, CYP oxidation increased already on the 14th day after the start of administration of the xenobiotic. At the same time, when a dose of 2.5 mg/kg was administered, no changes in the rate of reduction-oxidation of CYP were observed during this period. Longer administration of DEF (within 21 days) contributed to a more significant increase in CYP oxidation in microsomal fractions of the liver compared to a two-week administration of the xenobiotic under the conditions of administration of the two tested doses. It was shown that redox transformations of cytochrome b5 were activated at the initial stages of xenobiotic administration. An increase in the dose and timing of DEF administration was accompanied by a decrease in the transfer of electrons in the reductase chain of MOS.