ATP accelerates respiration of mitochondria from rat lung and suppresses their release of hydrogen peroxide.
J Bioenerg Biomembr
; 37(5): 327-38, 2005 Oct.
Article
em En
| MEDLINE
| ID: mdl-16341777
ABSTRACT
Lung mitochondria were isolated by differential centrifugation from pentobarbital-anesthetized male rats. One to three millimolar Mg2+-ATP increased the consumption of oxygen of lung mitochondria oxidizing 10 mM succinate > fourfold (P < 0.01) whereas ATP increased the respiration of liver mitochondria by < 35%. ATP also hyperpolarized partially uncoupled lung mitochondria in the presence of the mitochondria-specific antagonist, oligomycin. However, only 20% of the ATPase activity in the lung mitochondria was blocked by oligomycin compared to a blockade of 91% for liver mitochondria. We investigated the effect of reducing the non-mitochondrial ATPase activity in the lung preparation. A purer suspension of lung mitochondria from a Percoll gradient was inhibited 95% by oligomycin. The volume fraction identified as mitochondria by electron microscopy in this suspension (73.6+/- 3.5%) did not differ from that for liver mitochondria (69.1+/- 4.9%). ATP reduced the mean area of the mitochondrial profiles in this Percoll fraction by 15% (P <0.01) and increased its state 3 respiration with succinate as substrate by 1.5-fold (P < 0.01) with no change in the state 4 respiration measured after carboxyatractyloside. Hence, ATP increased the respiratory control ratio (state 3/state 4, P <0.01). In contrast, state 3 respiration with the complex 1-selective substrates, glutamate and malate, did not change with addition of ATP. The acceleration of respiration by ATP was accompanied by decreased production of H2O2. Thus ATP-dependent processes that increase respiration appear to improve lung mitochondrial function while minimizing the release of reactive oxygen species.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Consumo de Oxigênio
/
Difosfato de Adenosina
/
Trifosfato de Adenosina
/
Adenosina Trifosfatases
/
Peróxido de Hidrogênio
/
Pulmão
/
Mitocôndrias
Limite:
Animals
Idioma:
En
Revista:
J Bioenerg Biomembr
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
Estados Unidos