title: Dexamethasone treatment specifically increases the basal proton conductance of rat liver mitochondria.
abstract: We investigated the role that mitochondrial proton leak may play in the glucocorticoid-induced hypermetabolic state. Sprague-Dawley rats were injected with dexamethasone over a period of 5 days. Liver mitochondria and gastrocnemius subsarcolemmal and intermyofibrillar mitochondria were isolated from dexamethasone-treated, pair-fed and control rats. Respiration and membrane potential were measured simultaneously using electrodes sensitive to oxygen and to the potential-dependent probe triphenylmethylphosphonium, respectively. Five days of dexamethasone injection resulted in a marked increase in the basal proton conductance of liver mitochondria, but not in the muscle mitochondrial populations. This effect would have a modest impact on energy expenditure in rats.
authors.affiliation: Laboratoire de biochimie et de biologie moléculaire, INSERM EMI-U 00.18, Angers, France.
authors.forename: Damien
authors.initials: D
authors.lastname: Roussel
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Dumas
authors.forename: Antoine
authors.initials: A
authors.lastname: Augeraud
authors.forename: Olivier
authors.initials: O
authors.lastname: Douay
authors.forename: Françoise
authors.initials: F
authors.lastname: Foussard
authors.forename: Yves
authors.initials: Y
authors.lastname: Malthiéry
authors.forename: Gilles
authors.initials: G
authors.lastname: Simard
authors.forename: Patrick
authors.initials: P
authors.lastname: Ritz
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003907:Dexamethasone / Q000494:pharmacology*; D004435:Eating / Q000187:drug effects; D004553:Electric Conductivity; D017136:Ion Transport / Q000187:drug effects; D007700:Kinetics; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008930:Mitochondria, Liver / Q000187:drug effects / Q000502:physiology*; D008931:Mitochondria, Muscle / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects; D011522:Protons; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D011522:Protons; D003907:Dexamethasone