title: Effects of bone disease and calcium supplementation on antioxidant enzymes in postmenopausal women.
abstract: OBJECTIVE
  The study was aimed at investigating the effects of osteopenia and calcium supplementation on antioxidant enzyme activities (superoxide dismutase, SOD; catalase, CAT; and glutathione peroxidase, GPx) in postmenopausal women.
  
  
  METHODS
  Postmenopausal women (n=75) were divided into two groups, control (no bone disease) and osteopenia, according to their bone mineral density. Each group was still divided into calcium-supplemented and nonsupplemented sub-groups. Antioxidant enzyme activities were determined in whole blood using spectrophotometric methods.
  
  
  RESULTS
  CAT and SOD activities were not different among the studied groups. However, GPx activity was significantly higher in osteopenia groups as compared to control groups. Calcium supplementation had no effect on the parameters evaluated. Bone mineral density was negatively correlated with GPx activity (p<0.05).
  
  
  CONCLUSIONS
  Increased GPx activity could be interpreted as a defense response to counteract the overproduction of reactive oxygen species in women with osteopenia, and this effect was not prevented by calcium supplementation.
authors.affiliation: Programa de Pós-Graduação em Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS, Brazil.
authors.forename: Marla
authors.initials: M
authors.lastname: Hahn
authors.forename: Greicy M M
authors.initials: GM
authors.lastname: Conterato
authors.forename: Clarissa P
authors.initials: CP
authors.lastname: Frizzo
authors.forename: Paula R
authors.initials: PR
authors.lastname: Augusti
authors.forename: João C N
authors.initials: JC
authors.lastname: da Silva
authors.forename: Tais C
authors.initials: TC
authors.lastname: Unfer
authors.forename: Tatiana
authors.initials: T
authors.lastname: Emanuelli
mesh_terms: D000368:Aged; D000975:Antioxidants / Q000378:metabolism*; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000097:blood / Q000201:enzymology*; D002118:Calcium / Q000652:urine; D002136:Calcium, Dietary / Q000494:pharmacology*; D016022:Case-Control Studies; D002374:Catalase / Q000097:blood / Q000378:metabolism; D019587:Dietary Supplements; D005260:Female; D005979:Glutathione Peroxidase / Q000097:blood / Q000378:metabolism; D006801:Humans; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000097:blood / Q000201:enzymology; D017698:Postmenopause / Q000097:blood / Q000187:drug effects / Q000378:metabolism / Q000652:urine; D013482:Superoxide Dismutase / Q000097:blood / Q000378:metabolism
chemical_list: D000975:Antioxidants; D002136:Calcium, Dietary; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D002118:Calcium