Growth factor regulation of uncoupling protein-1 mRNA expression in brown adipocytes.
To study the effect of the mitogens epidermal growth factor (EGF), acidic and basic fibroblast growth factors (aFGF and bFGF), and vasopressin on brown adipocyte differentiation, we analyzed the expression of uncoupling protein-1 (UCP-1) mRNA. Quiescent brown preadipocytes express high levels of UCP-1 mRNA in response to triiodothyronine (T3) and norepinephrine (NE). The addition of serum or the mitogenic condition aFGF + vasopressin + NE or EGF + vasopressin + NE decreases UCP-1 mRNA. A second addition of mitogens further decreases UCP-1 mRNA. Treatment with aFGF or bFGF alone increases UCP-1 mRNA, whereas the addition of EGF or vasopressin dramatically reduces UCP-1 mRNA levels. The continuous presence of T3 increases UCP-1 mRNA levels in cells treated with EGF, aFGF, or bFGF. The effect of T3 on the stimulation of DNA synthesis also was tested. T3 inhibits the mitogenic activity of aFGF and bFGF. In conclusion, mitogens like aFGF or bFGF allow brown adipocyte differentiation, whereas EGF and vasopressin inhibit the differentiation process. T3 behaves as an important hormone that regulates both brown adipocyte proliferation and differentiation.
García
Bibian
B
Unidad de Endocrinología Molecular, Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas, 28029 Madrid, Spain.
Obregón
Maria-Jesús
MJ
D017667:Adipocytes / Q000166:cytology / Q000502:physiology*; D002001:Adipose Tissue, Brown / Q000166:cytology*; D000818:Animals; D001798:Blood Proteins / Q000494:pharmacology; D001833:Body Temperature Regulation / Q000502:physiology; D002352:Carrier Proteins / Q000235:genetics*; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D004815:Epidermal Growth Factor / Q000494:pharmacology; D016220:Fibroblast Growth Factor 1 / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D007473:Ion Channels; D008565:Membrane Proteins / Q000235:genetics*; D024101:Mitochondrial Proteins; D008934:Mitogens / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D014284:Triiodothyronine / Q000494:pharmacology; D000071256:Uncoupling Protein 1; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014667:Vasopressins / Q000494:pharmacology
D001798:Blood Proteins; D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D008934:Mitogens; D012333:RNA, Messenger; C000604373:Ucp1 protein, rat; D000071256:Uncoupling Protein 1; D014662:Vasoconstrictor Agents; D014284:Triiodothyronine; D016222:Fibroblast Growth Factor 2; D016220:Fibroblast Growth Factor 1; D014667:Vasopressins; D004815:Epidermal Growth Factor; D009638:Norepinephrine