title: Minimum Selenium Requirements Increase When Repleting Second-Generation Selenium-Deficient Rats but Are Not Further Altered by Vitamin E Deficiency.
abstract: Second-generation selenium-deficient weanling rats fed graded levels of dietary Se were used (a) to study the impact of initial Se deficiency on dietary Se requirements; (b) to determine if further decreases in selenoperoxidase expression, especially glutathione peroxidase 4 (Gpx4), affect growth or gross disease; and (c) to examine the impact of vitamin E deficiency on biochemical and molecular biomarkers of Se status. Rats were fed a vitamin E-deficient and Se-deficient crystalline amino acid diet (3 ng Se/g diet) or that diet supplemented with 100 μg/g all-rac-α-tocopheryl acetate and/or 0, 0.02, 0.05, 0.075, 0.1, or 0.2 μg Se/g diet as Na2SeO3for 28 days. Se-supplemented rats grew 6.91 g/day as compared to 2.17 and 3.87 g/day for vitamin E-deficient/Se-deficient and vitamin E-supplemented/Se-deficient groups, respectively. In Se-deficient rats, liver Se, plasma Gpx3, red blood cell Gpx1, liver Gpx1 and Gpx4 activities, and liver Gpx1 mRNA levels decreased to <1, <1, 21, 1.6, 49, and 11 %, respectively, of levels in rats fed 0.2 μg Se/g diet. For all biomarkers, ANOVA indicated significant effects of dietary Se, but no significant effects of vitamin E or vitamin E × Se interaction, showing that vitamin E deficiency, even in severely Se-deficient rat pups, does not result in compensatory changes in these biochemical and molecular biomarkers of selenoprotein expression. Se requirements determined in this study, however, were >50 % higher than in previous studies that started with Se-adequate rats, demonstrating that dietary Se requirements determined using initially Se-deficient animals can result in overestimation of Se requirements.
authors.affiliation: Department of Nutritional Sciences, University of Wisconsin, 1415 Linden Drive, Madison, WI, 53706, USA. sunde@nutrisci.wisc.edu.|Department of Nutritional Sciences, University of Missouri, Columbia, MO, 65211, USA. sunde@nutrisci.wisc.edu.
authors.forename: Roger A
authors.initials: RA
authors.lastname: Sunde
authors.affiliation: Department of Nutritional Sciences, University of Missouri, Columbia, MO, 65211, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Thompson
authors.affiliation: Department of Nutritional Sciences, University of Missouri, Columbia, MO, 65211, USA.
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Fritsche
authors.affiliation: Department of Nutritional Sciences, University of Wisconsin, 1415 Linden Drive, Madison, WI, 53706, USA.|Department of Nutritional Sciences, University of Missouri, Columbia, MO, 65211, USA.
authors.forename: Jacqueline K
authors.initials: JK
authors.lastname: Evenson
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D004032:Diet; D005260:Female; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats; D012643:Selenium / Q000008:administration & dosage / Q000172:deficiency* / Q000378:metabolism*; D014811:Vitamin E Deficiency / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D012643:Selenium
keywords: Biomarkers; Glutathione peroxidase; Phospholipid hydroperoxide glutathione peroxidase; Selenoprotein P; Transcript; mRNA; α-Tocopherol