López-Torres M, Pérez-Campo R, Barja de Quiroga G
Department of Animal Physiology (Animal Biology II), Faculty of Biology, Complutense University, Madrid, Spain.
Pharmacol Toxicol. 1990 Jan;66(1):27-31. doi: 10.1111/j.1600-0773.1990.tb00696.x.
In order to clarify the physiological role in vivo of H2O2-detoxifying enzymes at low and high levels of O2 tension we studied catalase (CAT), glutathione peroxidases (GP), and in vivo peroxidation (TBA-RS) in the lung and heart of Rana perezi frogs chronically treated with hyperoxia, aminotriazole (AT) -a CAT inhibitor-, or both. Hyperoxia did not change CAT, GP or TBA-RS. Aminotriazole caused an almost complete depletion of CAT, a 30% decrease of GP and a 132% (lung) to 200% (heart) increase of TBA-RS. Changes similar to these were found in the group treated with AT in hyperoxia. No mortality or changes in total or organ weight occurred in the experimental groups. Main conclusions are: (1) The maximal hyperoxia tolerance showed by frogs among vertebrates does not need antioxidant enzyme induction from lung or heart and is probably related to the presence of high constitutive levels of GP in relation to metabolic rate. (2) Even in normoxia the tissues present significant amounts of H2O2, and CAT is needed to avoid oxidative damage. GP does not compensate its absence. The implications of these results in relation to oxygen toxicity in man is discussed.
为了阐明在低氧和高氧张力条件下，过氧化氢解毒酶在体内的生理作用，我们研究了长期接受高氧、氨基三唑（AT，一种过氧化氢酶抑制剂）或两者处理的泽氏斑腿树蛙肺和心脏中的过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GP）以及体内过氧化反应（硫代巴比妥酸反应物，TBA-RS）。高氧并未改变CAT、GP或TBA-RS。氨基三唑导致CAT几乎完全耗尽，GP下降30%，TBA-RS在肺中增加132%，在心脏中增加200%。在高氧环境下用AT处理的组中也发现了类似的变化。实验组未出现死亡情况，总体重或器官重量也未发生改变。主要结论如下：（1）青蛙在脊椎动物中表现出的最大高氧耐受性并不需要肺或心脏诱导抗氧化酶，这可能与相对于代谢率而言，GP具有较高的组成水平有关。（2）即使在常氧条件下，组织中也存在大量过氧化氢，需要CAT来避免氧化损伤。GP无法弥补其缺失。本文还讨论了这些结果对人类氧中毒的影响。
