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This Article Full Text Full Text (PDF) All Versions of this Article: jas.2008-1301v1 87/9/2867    most recent Alert me when this article is cited Alert me if a correction is posted Services Related articles in J. Anim Sci. Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Brennan, K. M. Articles by Johnson, K. A. PubMed PubMed Citation Articles by Brennan, K. M. Articles by Johnson, K. A.

Body weight loss in beef cows: II. Increased antioxidant messenger ribonucleic acid levels in skeletal muscle but not erythrocyte antioxidant activity

Department of Animal Sciences, Washington State University, Pullman 99164

¹ Corresponding author: johnsoka{at}wsu.edu

Twenty-six Angus-cross cows were used to examine the effect of BW loss (WL) on skeletal muscle and erythrocyte markers of oxidative stress. Serum NEFA concentrations, erythrocyte superoxide dismutase, and glutathione peroxidase activities were measured during WL and BW maintenance. Real-time reverse-transcription-PCR was used to determine mRNA levels of antioxidant genes during both periods to assess skeletal muscle response to WL. Body weight loss resulted in elevated serum NEFA concentrations but no change in erythrocyte superoxide dismutase and glutathione peroxidase activities. During WL, mRNA levels of the antioxidant genes glutathione peroxidase 4, mitochondrial superoxide dismutase, thioredoxin reductase 1, and selenoprotein W increased. Abundance of mRNA of genes involved in antioxidant signaling, specifically, PPAR coactivator-1 , nuclear respiratory factor 1, estrogen-related receptor , and tumor protein 53, was also increased. In summary, during WL cows had no change in peripheral antioxidant enzyme activity, but mRNA abundance of proteins involved in protecting the body from oxidative stress increased in skeletal muscle. During times when NEFA are used as a fuel source, signals such as mild reactive oxygen species production or increased concentration of lipid by-products activate the transcription of nuclear signaling molecules such as PPAR gamma coactivator-1 , nuclear respiratory factor 1, estrogen-related receptor , and tumor protein 53. These genes work to activate antioxidant genes such as mitochondrial superoxide dismutase, glutathione peroxidase 4, and thioredoxin reductase 1 to aid in the detoxification of reactive oxygen species. These data suggest an important role for antioxidant genes to protect cattle that are mobilizing body fat.

Key Words: antioxidant • beef cattle • glutathione peroxidase • oxidative stress • skeletal muscle • superoxide dismutase

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