ENZYMATIC ACTIVITY OF THE DEHYDROGENASE AND OXIDASE FORMS OF XANTHINOXIDASE IN THE LIVER OF RATS UNDER THE CONDITIONS OF ω-3 POLYNUNSATURATED FATTY ACIDS AND RETINOIDS

Abstract

The effect of retinoid different doses in a complex with ω-3 polyunsaturated fatty acids (PUFA) on the enzyme activity of dehydrogenase (D-form – xanthine:NAD+-oxidoreductase, EC 1.17.1.4)) and oxidase (O-form – xanthine: oxygen oxidoreductase, EC 1.17.3.2) isoforms of xanthine oxidase and the generation of superoxide radical (O2•-) in the liver cytosolic fraction of rat are studied. Animals were divided into four groups: I – intact animals (control); II – rats injected with ω-3 PUFA at a dose of 120 mg/kg of animal weight; III, IV, V – animals administered retinol acetate at a dose of 60 IU/kg, 600 IU/kg, 1800 IU/kg, respectively; VI, VII, VIII – rats that were injected with a complex of ω-3 PUFAs and retinol acetate in doses of 60 IU/kg, 600 IU/kg, and 1800 IU/kg, respectively. Euthanasia of animals was performed under light ether anesthesia on the 14th day after the start of drug administration. It was established in-crease in total xanthine oxidase activity by 2.5 and 2.7 times compared to the values of the group of intact animals under the administering of a therapeutic dose of 600 IU/kg of retinol acetate and a maximum daily dose of 1800 IU/kg, respectively. The combined use of ω-3 PUFA and retinol acetate in doses of 600 IU/kg and 1800 IU/kg led to a decrease in the total xanthine oxidase activity in comparison with the values of animals that were administered the retinol acetate preparation separately in the corresponding doses. It is shown that the increase in the total activity of xanthine oxidase occurs due to the increase in the activity level of its O-form with a simultaneous decrease in the activity of the D-form. An increase of O-form xanthine oxidase activity in the liver cytosolic fraction the occurs in parallel with an increase in the rate of O2•- formation. This indicates the participation of this isoform in the induction of redox imbalance in the cytosol of liver cells under the influence of high doses of retinol acetate. The use of ω-3 PUFA along with retinol acetate contributes to the studied indicators normalization.