Effects of dietary vitamin E, C and soybean oil supplementation on antioxidant enzyme activities in liver and muscles of rats.

The effect of elevated levels of dietary vitamin E, C and a combination of vitamin E and C (E&C) with soybean oil on activities of antioxidant (AOE) enzymes important in the protection against lipid peroxidation was studied in male rats fed with vitamin C (12 mg/g), vitamin E (3.68 mg/g) or E&C (3.68 mg/kg+12 mg/g) supplemented diets for 28 days. Catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) activity in liver, pectoralis major (PM) and sartorius (S) muscles was increased significantly in rats fed with dietary vitamin C, E separately, and vitamin C&E combination, except, superoxide dismutase (SOD), which showed no alterations. These results clearly indicated that vitamin E&C separately and E&C together increased AOE activity in liver, PM and S muscle of rats. However, vitamin E and C combination enhanced AOE activity more significantly and our findings suggest the possible role of vitamin C&E and their combination in reducing the risk of chronic diseases related to oxidative stress.

Lipid peroxidation and antioxidant enzyme activity in different organs of mice exposed to low level of mercury.

The effects of mercuric chloride (Hg) on lipid peroxidation (LPO), glutathione reductase (GR), glutathione peroxidase (GPx), superoxide dismutase (SOD) and glutathione (GSH) levels in different organs of mice (CD-1) were evaluated. Mice were exposed (2 days/week) to 0.0 (control), 0.8 (low) and 8.0 (mid) and 80.0 (high) gHg/kg/day for 2 weeks. The high dose group was excluded from the study due to high mortality. LPO levels in kidney, testis and epididymus at low and mid doses; GR and GPx levels in testis at mid dose; SOD levels in brain and testis at both doses, liver and epididymus at mid dose; GSH levels in testis at both doses were significantly increased compared to their controls. However, the GR levels in kidney at both doses and in epididymus at mid dose; GPx levels in kidney and epididymus and SOD levels in kidney at both the doses; GSH levels in epididymus at mid dose were significantly decreased compared to their control. Body weight gain and food efficiency were significantly reduced (p<0.05) in mid dose. These results indicated that Hg treatment enhanced LPO in all tissues, but showed significant enhancement only in kidney, testis and epididymus suggesting that these organs were more susceptible to Hg toxicity. The increase in antioxidant enzyme levels in testis could be a mechanism protecting the cells against reactive oxygen species.

Effects of dietary proteins and trypsin inhibitor on growth and lipid metabolism in hamsters.

The purpose of this study was to determine trypsin inhibitor (TI) activity in sweetpotato and soy flour diets and their effects on the growth and lipid metabolism of hamsters. Male Golden Syrian hamsters were fed different types of dietary protein containing casein, soyprotein, transgenic sweetpotato plus soy flour (TSPF+SF), nontransgenic sweetpotato (NTSPF) plus soy flour (NTSPF+SF), transgenic sweetpotato (TSPF) and nontransgenic sweetpotato flour for 28 days. The TI activity was highest in TSPF+SF (19.30 TIU/mg) and NTSPF+SF (17.20 TIU/mg) diets that induced growth retardation in animals, lowest in TSPF (5.80 TIU/mg) and NTSPF (5.50 TIU/mg) diets, which did not affect the growth of the animals, and negligible in casein (<1.00 TIU/mg) and soyprotein (2.00 TIU/mg) diets. Plasma total cholesterol (TC), high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C) and triglyceride (TG) concentrations were significantly higher in hamsters fed the casein diet compared to those fed the soy protein, TSPF+SF, NTSPF+SF, TSPF and NTSPF diets. A positive correlation was observed between plasma TC concentrations of hamsters and dietary methionine, lysine, leucine content and methionine/glycine ratios. Liver TC and TG concentrations of hamsters fed casein were significantly higher than those of all other diet groups. The supplementation of sweetpotato flour with soy flour increased both protein and TI activity in the diets and the lipid metabolism of hamsters were unaffected by TI activity.

Uptake and distribution of mercury in rats after repeated administration of mercuric chloride.

This investigation was under taken to evaluate the effect of repeated exposure of mercuric chloride (MC) on food consumption, body weight gain and tissue distribution of mercury in rats. After two weeks of acclimation, male and female rats (45-50 days old) were orally gavaged with 0.00, 2.0, 4.0 6.0, 8.0 or 10.0 mg/kg/day of MC for 14 consecutive days. The mortality and food consumption were recorded daily. The body weight gains were recorded on day 0, 4, 7, 10, and at day of termination. At the end of the experiment, all surviving rats were euthanized and tissue samples from their brains, gonads, hearts, kidneys, livers, lungs, pancreases and spleens were collected and analyzed for mercury content. Exposure of male and female rats to 4.0 mg/kg/day of MC showed a significant reduction in body weight gain and food consumption when compared to their controls. However, at 2.0 mg/kg/day dose group showed no change of body gain and food consumption. The mercury contents in brains, gonads, hearts, and spleens of male and female rats at 0.0 and 2.0 mg/kg/day were undetectable. Both male and female rats accumulated significantly more mercury in the kidneys than the other organs. Mercury content in the kidneys of females was 39.9 and 40.9 microg/g at 2.0 and 4.0 mg/kg/day, respectively and of males was 34.9 and 41.0 microg/g at 2.0 and 4.0 mg/kg/day, respectively. However, mercury content in the kidneys and livers of males and females did not show any significant difference. Mercury content in the kidneys of both of sexes was significantly higher than the other organs.