The effects of red yeast rice extracts (RE) on adipocyte differentiation of 3T3-L1 cells were studied. RE were extracted from embryonic rice fermented with red yeast ( Monascus ruber). These extracts significantly decreased glycerol-3-phosphate dehydrogenase (GPDH) activity and lipid accumulation, a marker of adipogenesis, in a dose-dependent manner. Moreover, mRNA expression levels of both CCAAT/enhancer-binding protein (C/EBP) α and peroxisome proliferator-activated receptor (PPAR) γ, the key adipogenic transcription factors, were markedly decreased by RE. RE also inhibited the expression of PPARγ at protein levels. RE decreased significantly gene expression of adipocyte fatty acid binding protein (aP2) and leptin, which are adipogenic marker proteins and C/EBPα and PPARγ target genes. These results suggest that the inhibitory effect of RE on adipocyte differentiation might be mediated through the down-regulated expression of adipogenic transcription factors and other specific genes.
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