Up-regulation of uncoupling protein 3 by thyroid hormone, peroxisome proliferator-activated receptor ligands and 9-cis retinoic acid in L6 myotubes

摘要: Abstract Uncoupling protein 3 (UCP3), expressed abundantly in the skeletal muscle, is one of carrier proteins dissipating transmitochondrial electrochemical gradient as heat, and thereby has been implicated regulation energy metabolism. We have investigated UCP3 mRNA expression widely used L6 myocyte cell line by Northern blot analysis. was not detected myoblasts, but appeared after their differentiation to myotubes. The level increased when myotubes were treated with increasing concentrations triiodothyronine (T3), oleic acid, α-bromopalmitate carbacyclin, a non-selective ligand peroxisome proliferator-activated receptors (PPARs), whereas it influenced selective ligands PPARα (WY 14 643) PPARγ (troglitazone). A retinoid X receptor (RXR), 9-cis retinoic also effective itself combination carbacyclin stimulating expression. analysis individual PPAR isoforms revealed that significant PPARδ undetectable levels PPARγ. These results suggest myocytes differentiation-dependent regulated T3 receptor, RXR PPARδ.