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.
Dipartimento di Scienze della Vita, Seconda Università degli Studi di Napoli, Caserta, Italy.
A
A
Lanni
L
L
Beneduce
A
A
Lombardi
M
M
Moreno
O
O
Boss
P
P
Muzzin
J P
JP
Giacobino
F
F
Goglia
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