title: Effect of hyperoxia on oxygen free radical defense enzymes in the lung of zinc-deficient rats.
abstract: The effects of hyperoxia and the response of oxygen free radical defense enzymes in the lung and extracellular environment of the lung were measured in Zn-deficient rats. Although lung was the target organ as indicated by the increased lung:body weight ratio in all hyperoxia-exposed rats regardless of dietary regimen, 85% oxygen exposure seemed to impose a stress on the whole animal as indicated by decreased feed intake and body weight in ad libitum-fed rats. Hyperoxia exposure superimposed on Zn deficiency did not further reduce the feed intake or body weight of Zn-deficient rats. After 7 d of hyperoxia exposure, the Zn-repleted and ad libitum-fed groups consistently had increased activity of lung CuZn-superoxide dismutase (CuZnSOD), glutathione peroxidase and catalase; but changes in CuZnSOD activity were not related to lung Cu or Zn concentrations. Although Zn-deficient and pair-fed rats were unable to increase CuZnSOD activity, they had an increased lung Zn concentration compared with their air-exposed counterparts. Hyperoxia exposure also caused an increase in ceruloplasmin activity of pair-fed and ad libitum-fed control rats. We concluded that dietary Zn repletion started at the beginning of 85% oxygen exposure was effective for increasing the activity of the lung oxygen free radical defense enzymes, thus preventing hyperoxia-induced lung damage in Zn-deficient rats.
authors.affiliation: Department of Nutritional Sciences, College of Biological Science, University of Guelph, Ontario, Canada.
authors.forename: C G
authors.initials: CG
authors.lastname: Taylor
authors.forename: T M
authors.initials: TM
authors.lastname: Bray
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002374:Catalase / Q000378:metabolism; D002570:Ceruloplasmin / Q000378:metabolism; D003300:Copper / Q000097:blood; D004435:Eating / Q000187:drug effects; D005609:Free Radicals; D005979:Glutathione Peroxidase / Q000378:metabolism; D008168:Lung / Q000201:enzymology*; D008297:Male; D009929:Organ Size / Q000187:drug effects; D010088:Oxidoreductases / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism* / Q000633:toxicity*; D051381:Rats; D011919:Rats, Inbred Strains; D013482:Superoxide Dismutase / Q000378:metabolism; D015032:Zinc / Q000097:blood / Q000172:deficiency*
chemical_list: D005609:Free Radicals; D003300:Copper; D010088:Oxidoreductases; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D002570:Ceruloplasmin; D015032:Zinc; D010100:Oxygen