Dexamethasone treatment specifically increases the basal proton conductance of rat liver mitochondria.
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.
Roussel
Damien
D
Laboratoire de biochimie et de biologie moléculaire, INSERM EMI-U 00.18, Angers, France.
Dumas
Jean-François
JF
Augeraud
Antoine
A
Douay
Olivier
O
Foussard
Françoise
F
Malthiéry
Yves
Y
Simard
Gilles
G
Ritz
Patrick
P
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
D011522:Protons; D003907:Dexamethasone