title: [Peroxide metabolism on respiratory muscles: effect of growth, maturation and aging].
abstract: BACKGROUND
  Glutathione peroxidase (GSHPx) and catalase are two important cellular antioxidant enzymes involved in H2O2 and lipid-peroxide metabolism.
  
  
  OBJECTIVE
  To study the effects of growth, maturation and aging on the activity of these enzymes.
  
  
  METHODS
  GSHPx and catalase specific activities were measured in samples of diaphragm and intercostal muscle of male Sprague-Dawley rats of different ages (21, 50, 70, 180 and 365 days), anesthetised with chloral hydrate (45 mg/100 g i.p.).
  
  
  RESULTS
  The diaphragm and intercostal muscles did not differ in GSHPx activity at 21 days. After that, GSHPx activity increased progressively with age, but following a different pattern, in each muscle, suggesting an increase in enzyme substrates with age. In one year old animals, GSHPx activity was 5 times higher for the diaphragm and 3 times higher for the intercostal muscles, when compared with values observed at 21 days of age. Catalase activity also increased with age in the diaphragm but not in the intercostal muscles.
  
  
  CONCLUSIONS
  GSHPx activity increases progressively with age in rat respiratory muscles, with a time course that is specific of each muscle. Catalase activity increases with age only in the diaphragm. These results support the hypothesis that antioxidants in respiratory muscles undergo specific regulatory changes with age.
authors.affiliation: Departamento Enfermedades Respiratorias, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: L
authors.initials: L
authors.lastname: Montecinos
authors.forename: B
authors.initials: B
authors.lastname: Ramírez
authors.forename: C
authors.initials: C
authors.lastname: Lisboa
authors.forename: G
authors.initials: G
authors.lastname: Borzone
mesh_terms: D000367:Age Factors; D000375:Aging / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism*; D003964:Diaphragm / Q000201:enzymology; D005979:Glutathione Peroxidase / Q000378:metabolism*; D006128:Growth / Q000502:physiology*; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012132:Respiratory Muscles / Q000201:enzymology* / Q000502:physiology
chemical_list: D000975:Antioxidants; D006861:Hydrogen Peroxide; D002374:Catalase; D005979:Glutathione Peroxidase
vernacular_title: Metabolismo de peróxidos en músculos respiratorios: efecto del crecimiento, desarrollo y envejecimiento.