Catalase is needed to avoid tissue peroxidation in Rana perezi in normoxia.
1. In order to clarify the relative role of catalase (CAT) and glutathione peroxidases (GSH-Px) at normal and high O2 tensions, Rana perezi frogs were chronically treated with aminotriazole (AT), hyperoxia, or both. 2. A 100% survival was observed with both treatments. Hyperoxia increased liver catalase and kidney TBA-RS and decreased GSH-Px. 3. AT caused quantitatively higher alterations than hyperoxia in both organs: CAT was depleted, TBA-RS increased (114% in kidney) and GSH-Px decreased. 4. It is concluded that in Rana perezi (a) CAT, in spite of its much higher KM and Vmax in relation to GSH-Px, is needed to avoid oxidative stress even in normoxia; (b) normoxic tissues have significative amounts of H2O2; (c) GSH-Px does not compensate the lack of CAT.
Barja de Quiroga
G
G
Department of Animal Biology-II (Animal Physiology), Faculty of Biology, Complutense University, Madrid, Spain.
López-Torres
M
M
Pérez-Campo
R
R
D000640:Amitrole / Q000494:pharmacology; D000818:Animals; D002374:Catalase / Q000037:antagonists & inhibitors / Q000502:physiology*; D005979:Glutathione Peroxidase / Q000502:physiology; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D010084:Oxidation-Reduction; D010100:Oxygen / Q000494:pharmacology*; D010545:Peroxides / Q000378:metabolism*; D011898:Ranidae; D013858:Thiobarbiturates
D010545:Peroxides; D013858:Thiobarbiturates; D002374:Catalase; D005979:Glutathione Peroxidase; C029684:thiobarbituric acid; D010100:Oxygen; D000640:Amitrole