Occurrence of Selenoprotein Enzyme Activities and mRNA in Bovine Mammary Tissue

Abstract

To elucidate the possible role of selenoproteins for milk formation and mammary gland physiology, the activities of selenoprotein enzymes and the expression of selenoprotein genes were studied in the bovine mammary gland. Messenger RNA was demonstrated for selenoprotein P, thioredoxin reductase 1, and for glutathione peroxidase (GPx) 1, 3, and 4. Significant differences in mRNA expression between the cows were seen for GPx 1 and GPx 3. The enzyme activity of glutathione peroxidase varied approximately 16-fold among cows, and the activity of thioredoxin reductase and the concentration of soluble Se varied approximately 6-fold among cows. There were positive correlations between glutathione peroxidase activity, thioredoxin reductase activity, and soluble Se, the correlation between glutathione peroxidase activity and soluble Se being the strongest. Furthermore, selenoprotein P expression correlated with GPx 1 mRNA expression and with soluble Se. There was also a correlation between glutathione peroxidase activity and the mRNA expression of GPx 1. The general conclusion from the data was that the activity of glutathione peroxidase and thioredoxin reductase and the mRNA expression of selenoprotein P and GPx 1 and 3 were influenced by Se status, but the expression of GPx 4 and thioredoxin reductase 1 were not. These results indicate that the Se status in mammary tissue is an important regulator of selenoprotein activity and expression, but that other factors are also in operation.

Post-Translational Protein Deimination Signatures in Serum and Serum-Extracellular Vesicles of Bos taurus Reveal Immune, Anti-Pathogenic, Anti-Viral, Metabolic and Cancer-Related Pathways for Deimination

“…It is a plasma glycoprotein, mainly secreted from liver but also other tissues and contains most of the selenium in mammalian plasma [187][188][189]. In the cow roles for selenoproteins in mammary gland physiology and in milk formation have been identified [190] and roles for responses to oxidative stress in bovine arterial endothelial cells have also been suggested [191]. It has antioxidant properties [188] and serves in homeostasis and distribution of selenium [189].…”

Effects of retinoic acid on the synthesis of selenoprotein and the antioxidative indices of bovine mammary epithelial cells in vitro

“…Many enzymes, such as CAT, SOD, and T-AOC and selenoproteins of GPX, TRXR, and SELP, act as an important part to control oxidative stress, which protects the cells from oxidative stressinduced damage (Bruzelius et al 2007;Sordillo et al 2007). The antioxidant enzymes SOD and CAT play a crucial role as protective enzymes against radicals in tissues and are comprised in the cellular antioxidant defense system .…”

Selenium‐enriched Saccharomyces cerevisiae improves growth, antioxidant status and selenoprotein gene expression in Arbor Acres broilers

“…Bruzelius et al. () reported that Se levels influenced the GP X ‐1 mRNA levels, but not the GP X ‐4 mRNA levels. Venardos et al.…”

“…685 mg/kg Se were significantly decreased by 75% and 60%, respectively, compared with controls (Se, 0.21 mg/ kg), by week 6. Bruzelius et al (2007) reported that Se levels influenced the GP X -1 mRNA levels, but not the GP X -4 mRNA levels. Venardos et al (2005) also reported that Se deficiency significantly decreased the GP X -1 and GP X -4 mRNA levels, but Se supplementation (1.0 mg/kg) significantly increased the GP X -1 and GP X -4 mRNA levels in the heart of rats.…”