Alterations of rat liver mitochondrial oxidative phosphorylation and calcium uptake by benzo[a]pyrene

Salazar, I.; Pavani, M.; Aranda W.; Maya, JD; Morello A.; Ferreira J.

Abstract

We report that oxidative phosphorylation and Ca2+ uptake processes are enhanced in liver mitochondria isolated from benzo[a]pyrene (B[a]P)-treated rats. The carcinogen did not affect either the respiratory control index or the Ca2+ control ratio. B[a]P treatment increased the oxidation rate of several substrates that donate electrons at the level of all three coupling sites, either the ADP- or Ca2+-stimulated rates or those observed after ADP or Ca2+ exhaustion. However, the efficiency of energy coupling was maintained because both ADP/O and Ca2+/site ratios remained unchanged. The electron flow through NADH-oxidase, NADH-duroquinone reductase, NADH-juglone reductase, NADH-cytochrome c reductase, succinate-cytochrome c reductase, and cytochrome c oxidase was enhanced by B[a]P; however, succinate dehydrogenase activity was not affected. All these effects depended on the time post B[a]P administration, with a greater increase close to 48 h after administration of the carcinogen. The contents of cytochromes b, c1, and a + a3 from liver mitochondria, especially those isolated 48 h after B[a]P, were also significantly increased, although cytochrome c levels was just lightly increased 24 h after B[a]P treatment. These results suggest that B[a]P treatment stimulates mitochondrial respiration by increasing the level of several components of the mitochondrial respiratory chain. This may reflect mitochondrial adaptation to the cellular energy requirements of cell division in the neoplastic transformation process. © 2004 Elsevier Inc. All rights reserved.

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Título según WOS: Alterations of rat liver mitochondrial oxidative phosphorylation and calcium uptake by benzo[a]pyrene
Título según SCOPUS: Alterations of rat liver mitochondrial oxidative phosphorylation and calcium uptake by benzo[a]pyrene
Título de la Revista: TOXICOLOGY AND APPLIED PHARMACOLOGY
Volumen: 198
Número: 1
Editorial: ACADEMIC PRESS INC ELSEVIER SCIENCE
Fecha de publicación: 2004
Página de inicio: 1
Página final: 10
Idioma: English
URL: http://linkinghub.elsevier.com/retrieve/pii/S0041008X04001449
DOI:

10.1016/j.taap.2004.02.013

Notas: ISI, SCOPUS