Normobaric hyperoxic stress in budgerigars: non-enzymic antioxidants.
The effects of oxygen exposure on pulmonary and blood non-enzymic antioxidant concentrations was evaluated in budgerigars (Melopsittacus undulatus). Budgerigars were exposed to acute (3 h), repeated acute (3 exposures each of 3 h) or chronic (72 h) normobaric hyperoxic environments and the pulmonary and plasma concentrations of selected non-enzymic antioxidants, namely glutathione, uric acid, alpha- and gamma-tocopherol and carotenoids were assayed. With increasing duration of oxygen exposure, the ratio of oxidised to reduced glutathione was significantly increased, while the concentrations of uric acid, alpha- and gamma-tocopherol and carotenoids were significantly reduced, especially following chronic oxygen exposure. Following acute and repeated acute exposure, alteration in glutathione concentrations and reduction in alpha-tocopherol concentrations indicated oxygen stress. Following chronic exposure, depletion of non-enzymic antioxidants indicated exhaustion of these protective mechanisms and progression from oxygen stress to oxygen toxicity.
Jaensch
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Division of Veterinary and Biomedical Science, Murdoch University, South Street, Murdoch, WA, 6150, Australia. jaensch@numbat.murdoch.edu.au
Cullen
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Morton
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Raidal
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SR
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002338:Carotenoids / Q000097:blood / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D018496:Hyperoxia / Q000097:blood / Q000378:metabolism*; D008168:Lung / Q000187:drug effects* / Q000378:metabolism; D010100:Oxygen / Q000633:toxicity*; D010311:Parrots; D014527:Uric Acid / Q000378:metabolism; D014810:Vitamin E / Q000097:blood / Q000378:metabolism
D000975:Antioxidants; D014810:Vitamin E; D014527:Uric Acid; D002338:Carotenoids; D005978:Glutathione; D010100:Oxygen