Comparison of age-related differences in expression of phospholipid hydroperoxide glutathione peroxidase mRNA and activity in various tissues of pigs.
Phospholipid hydroperoxide glutathione peroxidase (PHGPX) is the second identified Se-dependent intracellular glutathione peroxidase (PHGPX) that reduces phospholipid hydroperoxides. The objective of this study was to determine the developmental regulation of PHGPX expression in tissues of neonatal, weanling and finishing pigs (Sus scrofa) compared with the expression of the classic Se-dependent cellular glutathione peroxidase (GPX) and the Se-independent enzyme, glutathione S-transferase (GST). Eight different tissues were collected from Se-adequate male pigs aged 1, 28 and 180 days, and supernatant of the tissue homogenate was assayed for PHGPX, GPX and GST activities by using phosphatidylcholine hydroperoxide, hydrogen peroxide and 1-chloro-2,4-dinitrobenzene as substrate, respectively. Total RNA was isolated from four tissues and assayed for PHGPX mRNA expression. Both mRNA and activity expression of PHGPX in most assayed tissues was increased as pigs became older (P < 0.05), but increases in PHGPX mRNA levels between ages did not fully account for all changes in activity. Expression of GPX activity was increased more than that of PHGPX between day 1 and day 28 (P < 0.0001). Expression of GST activity in various tissues was also affected by age (P < 0.01) but lacked a consistent relationship with the changes in GPX and PHGPX activity. Tissue-specific patterns of developmental expression of these enzymes may be related to the susceptibility of organs to pro-oxidant injuries. In conclusion, expression of PHGPX mRNA and activity in various tissues of pigs is developmentally increased over ages, and the pattern is somewhat different from that of GPX.
Lei
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XG
Department of Animal Science, Cornell University, Ithaca, NY 14853, USA. XL20@cornell.edu
Ross
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DA
Roneker
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KR
D000375:Aging / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D004137:Dinitrochlorobenzene / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D005979:Glutathione Peroxidase / Q000235:genetics* / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D008054:Lipid Peroxides / Q000378:metabolism; D008297:Male; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012643:Selenium / Q000378:metabolism; D013552:Swine / Q000254:growth & development / Q000378:metabolism*
D004137:Dinitrochlorobenzene; D008054:Lipid Peroxides; D012333:RNA, Messenger; D006861:Hydrogen Peroxide; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D005979:Glutathione Peroxidase; D005982:Glutathione Transferase; D012643:Selenium