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.
Division of Veterinary and Biomedical Science, Murdoch University, South Street, Murdoch, WA, 6150, Australia. jaensch@numbat.murdoch.edu.au
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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