Tolerance of Diets Deficient or Excessive in Selenium by Syrian Hamsters

Birt, Diane F.; Julius, Alan D.; Runice, Christopher E.; Sayed, Soad

doi:10.1159/000176627

Cited by 13 publications

(4 citation statements)

References 27 publications

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“…Approximately 98% of blood GSH-PX activity in dairy cattle is associated with erythrocytes [4] and the erythrocytic GSH-PX activity correlates highly with the level of selenium in blood [2,34], The esti mation of erythrocytic GSH-PX activity in the present study revealed a significant in crease of this enzyme in organic and inor ganic toxicity, which is in accordance with the observations of other workers [2,3,13,17,20,33,34]. Though significant increase in erythrocyte GSH-PX was observed on the 20th day of experimental feeding of seleni um-rich feed, the maximum activity was no ticed on 30-40 days.…”

Section: Discussionsupporting

confidence: 91%

Experimental Selenium Toxicity in Guinea Pigs: Biochemical Studies

Das

Sadana²,

Gupta³

et al. 1989

Ann Nutr Metab

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Biochemical studies were conducted in experimentally induced selenium toxicity in recently weaned guinea pigs. A significant drop in blood glucose level, in comparison to controls, was observed in animals fed selenium-enriched barley (organic form) as well as those fed ordinary barley mixed with sodium selenite (inorganic form). Estimation of total serum proteins also revealed a significant drop in both these groups. SGOT (EC 2.6.1.1) activity was comparatively lower but no significant alteration was noticed in SGPT (EC 2.6.1.2). The erythrocytic glutathione peroxidase activity was significantly increased in inorganic selenosis followed by that in organic one, in comparison to controls. All these alterations were of mild degree in guinea pigs which were given sodium arsenite (10 ppm) along with sodium selenite (30 ppm) in the feed.

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Section: Discussionsupporting

confidence: 91%

Experimental Selenium Toxicity in Guinea Pigs: Biochemical Studies

Das

Sadana²,

Gupta³

et al. 1989

Ann Nutr Metab

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“…Following the acclimatization period, hamsters were fed for three wk one of four diets (Table 1) which consisted of: i) Control (CT) containing formulated basal requirements of α-Toc and Se; ii) CT + α-toc (67 IU all-racemic α-tocopheryl acetate/kg diet); iii) CT + Se (3.4 mg Se/kg diet); iv) CT + α-Toc (67 IU all-racemic α-tocopheryl acetate/kg diet) + Se (3.4 mg Se/kg diet). The pharmacological supplemental level of Se (3.4 ppm/kg diet) was chosen to be equivalent to two-thirds of the non-toxic 5 ppm Se/kg diet dose fed previously to Syrian hamsters for 25 wk 50. Subacute toxicity of Se has been tested in previous work, which found levels of dietary Se up to 10 ppm to be non-toxic to Syrian hamsters 51,52.…”

Section: Methodsmentioning

confidence: 99%

“…The pharmacological supplemental level of Se (3.4 ppm/kg diet) was chosen to be equivalent to two-thirds of the non-toxic 5 ppm Se/kg diet dose fed previously to Syrian hamsters for 25 wk. 50 Subacute toxicity of Se has been tested in previous work, which found levels of dietary Se up to 10 ppm to be non-toxic to Syrian hamsters. 51,52 The levels of α-Toc in the basal diet were chosen based on National Research Council (NRC) recommendations for the hamster of 27 IU all-racemic α-tocopheryl acetate/kg diet (10 tocopherol equivalents = 10 mg all-racemic α-tocopherol = 15 IU).…”

Section: Materials and Methods Experiments 1-animals Diets And Samplmentioning

confidence: 99%

Antioxidant Supplements Improve Profiles of Hepatic Oxysterols and Plasma Lipids in Butter-fed Hamsters

Poirier

Cockell

Ratnayake

et al. 2010

Nutr Metab Insights

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Hypercholesterolemic diets are associated with oxidative stress that may contribute to hypercholesterolemia by adversely affecting enzymatically-generated oxysterols involved in cholesterol homeostasis. An experiment was conducted to examine whether the cholesterol-lowering effects of the antioxidants selenium and α-tocopherol were related to hepatic oxysterol concentrations. Four groups of male Syrian hamsters (n = 7–8) were fed high cholesterol and saturated fat (0.46% cholesterol, 14.3% fat) hypercholesterolemic semi-purified diets: 1) Control; 2) Control + α-tocopherol (67 IU all-racemic-α-tocopheryl-acetate/kg diet); 3) Control + selenium (3.4 mg selenate/kg diet); and 4) Control + α-tocopherol + selenium. Antioxidant supplementation was associated with lowered plasma cholesterol concentrations, decreased tissue lipid peroxidation and higher hepatic oxysterol concentrations. A second experiment examined the effect of graded selenium doses (0.15, 0.85, 1.7 and 3.4 mg selenate/kg diet) on mRNA expression of the oxysterol-generating enzyme, hepatic 27-hydroxylase (CYP27A1, EC 1.14.13.15), in hamsters (n = 8–9) fed the hypercholesterolemic diets. Supplementation of selenium at 3.4 mg selenate/kg diet was not associated with increased hepatic 27-hydroxylase mRNA. In conclusion, the cholesterol lowering effects of selenium and α-tocopherol were associated with increased hepatic enzymatically generated oxysterol concentrations, which appears to be mediated via improved antioxidant status rather than increased enzymatic production.

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“…Blood and tissue Se concentrations were [34,35], Recent studies [36] in our laboratory using several dietary Se levels between 0 and 10 ppm for 25 weeks have demonstrated that plasma and erythrocyte GSH-Px activity in hamsters increases with Se, with peak activ ity at Se levels of 5-10 ppm. In this study, the highest GSH-Px activity was also observed in the 10 ppm Se-fed group.…”

Section: Discussionmentioning

confidence: 91%

Toxic Effects of Dietary Selenium in the Syrian Hamster

Julius¹,

Davies²,

Birt³

1983

Ann Nutr Metab

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Selenium (Se) toxicity and utilization was evaluated in hamsters fed casein- and torula yeast-based diets. 4-week-old hamsters received semipurified diets for 21 days. In experiment I diets were supplemented with either 0.25, 10, 20, 40 or 80 ppm Se as sodium selenite (SS) and in experiment II diets were supplemented with 0.1 5.0 or 10.0 ppm as SS or selenomethionine (SM). Blood and tissue Se concentrations and glutathione peroxidase (GSH-Px) activity were measured at the termination of the feeding period. In both studies growth rate was depressed and food consumption decreased in hamsters given diets supplemented with 10 ppm or greater SS. Mortality associated with Se toxicity occurred only in females fed the 80 ppm Se-supplemented diet. Whole blood and tissue Se concentrations rose with increasing dietary Se and occurred up to the 80 ppm Se level in blood. Liver, kidney and lung Se concentrations were higher in hamsters fed SM than for those fed SS. Plasma GSH-Px activity was not significantly affected by increasing dietary Se levels, and hamsters fed dietary Se levels above 10 ppm did not have increased erythrocyte GSH-Px activity associated with increased blood Se concentrations. Liver GSH-Px activity was higher in SM-fed hamsters. The results suggest that dietary Se, fed as SS, becomes toxic for Syrian hamsters at levels of 10 ppm and above.

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Tolerance of Diets Deficient or Excessive in Selenium by Syrian Hamsters

Cited by 13 publications

References 27 publications

Experimental Selenium Toxicity in Guinea Pigs: Biochemical Studies

Experimental Selenium Toxicity in Guinea Pigs: Biochemical Studies

Antioxidant Supplements Improve Profiles of Hepatic Oxysterols and Plasma Lipids in Butter-fed Hamsters

Toxic Effects of Dietary Selenium in the Syrian Hamster

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