Triiodothyronine induces the transcription of the uncoupling protein gene and stabilizes its mRNA in fetal rat brown adipocyte primary cultures.
Confluent fetal rat brown adipocytes in primary culture showed an almost undetectable level of uncoupling protein (UCP) mRNA and a low mitochondrial content of functional UCP. Treatment of confluent cells with 10 nM triiodothyronine in a serum-free medium, in the absence of noradrenergic stimulation, increased the amount of UCP mRNA in a time-dependent manner. This effect was due to an increased UCP gene transcription rate and UCP mRNA stabilization, resulting in a higher content of immunoreactive mitochondrial UCP and functional UCP (detected by its ability to bind GDP). Thus, triiodothyronine might play a significant physiological role in the UCP expression throughout fetal development, when brown adipose tissue starts to differentiate and UCP is primarily expressed.
Guerra
C
C
Departamento de Bioquimica y Biologia Molecular II, Universidad Completense Facultad de Farmacia, Madrid, Spain.
Roncero
C
C
Porras
A
A
Fernández
M
M
Benito
M
M
D002001:Adipose Tissue, Brown / Q000502:physiology*; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics*; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D006153:Guanosine Diphosphate / Q000378:metabolism; D007473:Ion Channels; D008565:Membrane Proteins / Q000235:genetics*; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins; D009638:Norepinephrine / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D014158:Transcription, Genetic / Q000187:drug effects*; D014284:Triiodothyronine / Q000494:pharmacology*; D000071256:Uncoupling Protein 1
D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D000071256:Uncoupling Protein 1; D014284:Triiodothyronine; D006153:Guanosine Diphosphate; D003513:Cycloheximide; D009638:Norepinephrine