Cold-induced changes in the energy coupling and the UCP3 level in rodent skeletal muscles.
The mechanism of thermoregulatory uncoupling of respiration and phosphorylation in skeletal muscles has been studied. It is found that 24 h cold exposure results in (i) a 3-fold increase in the amount of UCP3 protein in rat skeletal muscle mitochondria, and (ii) pronounced lowering of the membrane potential in isolated rat or mouse skeletal muscle mitochondria. The decrease in membrane potential is reversed by adding bovine serum albumin. Cold exposure is also found to sensitize the membrane potential to the uncoupling action of added fatty acid (laurate). After laurate addition, the recoupling effects of GDP and carboxyatractylate decrease whereas that of albumin increases in mitochondria from cold-treated rats or mice. Changes similar to those induced by cold can be initiated by the in vivo addition of thyroxine. Cold exposure does not affect energy coupling in liver mitochondria. The possible involvement of UCP3 isoforms in nucleotide-sensitive and -insensitive uncoupling is discussed.
Simonyan
R A
RA
Department of Bioenergetics, AN Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia.
Jimenez
M
M
Ceddia
R B
RB
Giacobino
J P
JP
Muzzin
P
P
Skulachev
V P
VP
D000818:Animals; D001833:Body Temperature Regulation; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003080:Cold Temperature; D004734:Energy Metabolism; D007425:Intracellular Membranes / Q000737:chemistry / Q000378:metabolism; D007473:Ion Channels; D007848:Laurates / Q000494:pharmacology; D008564:Membrane Potentials; D051379:Mice; D008930:Mitochondria, Liver / Q000378:metabolism; D008931:Mitochondria, Muscle / Q000378:metabolism; D024101:Mitochondrial Proteins; D018482:Muscle, Skeletal / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D012710:Serum Albumin, Bovine; D013974:Thyroxine; D014475:Uncoupling Agents / Q000378:metabolism; D000071247:Uncoupling Protein 3
D002352:Carrier Proteins; D007473:Ion Channels; D007848:Laurates; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; C000604393:Ucp3 protein, mouse; C000604394:Ucp3 protein, rat; D014475:Uncoupling Agents; D000071247:Uncoupling Protein 3; D012710:Serum Albumin, Bovine; D013974:Thyroxine