Effect of dietary fat on vitamin status of rats

The influence of low (1%) and high (31%) diet fat content (sunflower-seed oil and lard 1:1 at a ratio of 1:1) on vitamin A, E, B1 and B2 status of growing Wistar rats (8 rats per group) with initial body weight 80-100 g has been investigated. The semi-synthetic diet contained vitamin mixture in doses covering the physiological requirement of these animals. The increase of fat content (31%) in the diet due to the presence of vitamin E in sunflower-seed oil automatically lead to 1,7-fold increase consumption of this vitamin compared to the control group. Diet fat content did not affect the level of vitamins B1 and B2 in rat liver. Excessive intake of fat and vitamin E for 6 weeks did not influence on the content of blood plasma vitamin E and rat liver vitamin A occurs at the same time, while significant 1,9 fold elevation of liver vitamin E level and 26 per cent increase of blood plasma vitamin A concentration. The almost complete exclusion of fat from the diet had no effect on blood plasma level of alpha-tocopherol and retinol, but resulted in a significant decrease of vitamins A and E content in rat liver by 40 per cent, indicating a deterioration of sufficiency with these fat-soluble vitamins. The analysis of the results obtained in this investigation and literature data have suggested that under excessive as well as under decreased consumption of fat there is a risk of the development of polyhypovitaminosis. Vitamin complex supplementation is required to prevent a possible worsening of vitamin status under diets with modified fatty component.     

Effects of dietary fat level on the xenobiotic metabolism enzymes activity and antioxidant enzymes in rats

Male Wistar rats received fat-free diet or diets containing 5, 10 and 30% of fat (sunflower oil + lard, 1:1) for 4 weeks. The direct relationship between dietary fat level and ethoxyresorufin O-dealkylase activity of CYP1A1, methoxyresorufin O-dealkylase activity of CYP1A2, pentoxyresorufin O-dealkylase activity of CYP2B1 and testosterone 6beta-hydroxylase activity of CYP3A was found. Activities of key enzymes of phase II xenobiotic metabolism (total activity of glutathione transferase, activity of UDP-glucuronosyle transferase) and antioxidant enzymes (catalase, glutathione peroxidase, glutathione reductase, paraoxonase-1 and heme oxygenase-1) also increased with higher dietary fat level.     

Effects of polyvitamin deficiency on the activity of xenobiotic-metabolizing enzymes in rat liver

The activity of xenobiotic-metabolizing enzymes was studied in the liver of male Wistar rats, which were fed for 4 weeks diets, containing 100 (control), 50 and 20% of vitamin adequate level. Moderate (50%) polyvitamin deficiency increased activity of EROD (by 13%), MROD (by 34%; p<0,05), 4-nitrophenol hydroxylase (by 16%), 6beta-testosterone hydroxylase (by 17%), UDP-glucuronosyle transferase (by 26%, p<0,05) and quinone reductase (by 55%, p<0,05). Deep (20%) polyvitamin deficiency decreased in liver activity of MROD (to 78% of control level, p<0,05), 4-nitrophenol hydroxylase (to 74%, p<0,05), heme oxygenase-1 (to 83%, p<0,05) and quinone reductase (to 60%, p<0,05). At the same time a 22% increase in the UDP-glucuronosyle transferase activity compared to the control group was found; activities of EROD, PROD, 6beta-testosterone hydroxylase and the total activity of glutathione S-transferase were unchanged. Deep polyvitamin deficiency had no significant effect on CYP1A1 mRNA and AhR mRNA level, whereas the expression of CYP1A2 mRNA and CYP3A1 mRNA were decreased to 62 and 79%, respectively, as compared with control.     

Preparation of magnetic composites through SrO-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript>-B<Subscript>2</Subscript>O<Subscript>3</Subscript> glass crystallization

Glasses with nominal compositions 11SrO · 5.5Fe₂O₃ · 4.5Al₂O₃ · 4B₂O₃ (1) and 15SrO · 5.5Fe₂O₃ · 4.5Al₂O₃ · 4B₂O₃ (2) were prepared by rapidly quenching oxide melts between counterrotating steel rollers. The glasses were then heat-treated in the range 650–950°C to produce glass-ceramic samples. The samples were characterized by X-ray diffraction, electron microscopy, and magnetic measurements. The phase composition of the glass-ceramics was determined, and their microstructure and magnetic properties were studied. The annealing temperature was shown to have a strong effect on the coercivity of the materials, which reaches 650 and 570 kA/m for compositions 1 and 2, respectively.