Expression of uncoupling protein-3 and mitochondrial activity in the transition from hypothyroid to hyperthyroid state in rat skeletal muscle.
We sought a correlation between rat skeletal muscle triiodothyronine (T3)-mediated regulation of uncoupling protein-3 (UCP3) expression and mitochondrial activity. UCP3 mRNA expression increased strongly during the hypothyroid-hyperthyroid transition. The rank order of mitochondrial State 3 and State 4 respiration rates was hypothyroid < euthyroid < hyperthyroid. The State 4 increase may have been due to the increased UCP3 expression, as the proton leak kinetic was stimulated in the hypothyroid-hyperthyroid transition and a good correlation exists between the State 4 and UCP3 mRNA level. As a significant proportion of an organism's resting oxygen consumption is dedicated to opposing the proton leak, skeletal muscle mitochondrial UCP3 may mediate part of T3's effect on energy metabolism.
Lanni
A
A
Dipartimento di Scienze della Vita, Seconda Università degli Studi di Napoli, Caserta, Italy.
Beneduce
L
L
Lombardi
A
A
Moreno
M
M
Boss
O
O
Muzzin
P
P
Giacobino
J P
JP
Goglia
F
F
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics*; D004734:Energy Metabolism / Q000187:drug effects; D005786:Gene Expression Regulation / Q000235:genetics; D006980:Hyperthyroidism / Q000378:metabolism; D007037:Hypothyroidism / Q000378:metabolism; D007473:Ion Channels; D007700:Kinetics; D008297:Male; D008931:Mitochondria, Muscle / Q000378:metabolism*; D024101:Mitochondrial Proteins; D018482:Muscle, Skeletal / Q000378:metabolism*; D010101:Oxygen Consumption; D011522:Protons; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014284:Triiodothyronine / Q000494:pharmacology; D000071247:Uncoupling Protein 3
D002352:Carrier Proteins; D007473:Ion Channels; D024101:Mitochondrial Proteins; D011522:Protons; D012333:RNA, Messenger; C000604394:Ucp3 protein, rat; D000071247:Uncoupling Protein 3; D014284:Triiodothyronine