EFFECT OF FATTY-ACID COMPOSITION, CADMIUM AND VITAMIN-E INTAKE ON PROOXIDATIVE-ANTIOXIDATIVE STATE OF RAT-LIVER

The effect of cadmium intake (100 mu g/kg body weight/day as cadmium c hloride over a period of three months) on the prooxidative-antioxidati ve state of liver was studied in 30 days old weaned male rats. Animals were fed a nutritionally balanced lacto-vegetable diet containing hig h-quality amino acid mixture (casein + gluten 1:1), lipids in form of either pork fat PF (% of polyunsaturated fatty acids PUFA = 11.9; unsa turation index UI = 72), margarine MA (% PUFA = 21.9; UI = 98), or soy bean oil SO (% PUFA = 61.2; UI = 156) and vitamin E at amount of 60 mg /kg of food (groups PF, PF + Cd, MA, MA + Cd, SO, SO + Cd) or 600 mg ( groups PF + Cd + E, MA + Cd + E, SO + Cd + E) in form of alpha-tocophe ryl acetate. The following parameters were measured: conjugated dienes of fatty acids (CD), activities of superoxide dismutase (SOD), catala se (CAT) (as relative generation of H2O2) and glutathione peroxidase ( GSH-Px). A direct relation between lipoperoxidation values and unsatur ation index of lipids was found both in spontaneous (PF, MA, SO - cont rol) and cadmium-induced generation of free oxygen radicals. Cadmium i ntake resulted in a disbalance in prooxidative-antioxidative processes which was manifested in a significant increase of CD in all fat sourc es (the degree of increase was directly proportional to UI and PUFA), in similar values of relative H2O2 generation and in a nonsignificant increase of GSH-Px in animals with most developed lipo peroxidation (S O). A tenfold increase in the administered dose of vitamin E restored a prooxidative-antioxidative equilibrium disturbed by cadmium intake i n the liver of rats fed the diet with animal fat (PF + Cd + E) and mar garine (MA + Cd + E) (reduction of CD to the level of control groups, decrease of relative generation of H2O2 - significant in MA). In anima ls fed with soybean oil, a vitamin E - induced reduction of CD was sig nificantly over the control level simultaneously with significant stim ulation of GSH-Px activity. No changes in H2O2 generation together wit h CD levels and GSH-Px activity indicated that a synergic effect of se veral antioxidants is essential in the case of high lipoperoxidation. Presented results are important with respect to possible control or re gulation of the equilibrium between prooxidative and antioxidative pro cesses by nutrition.