Ginsenoside Rb 1 promotes adipogenesis in 3T3-L1 cells by enhancing PPARγ 2 and C/EBPα gene expression

Abstract

Evidence has accumulated that ginseng and its main active constituents, ginsenosides, possess anti-diabetic and insulin-sensitizing properties which may be partly realized by regulating adipocyte development and functions. In the present study, we explored the effect of ginsenoside Rb 1, the most abundant ginsenoside in ginseng root, on adipogenesis of 3T3-L1 cells. We found that with standard differentiation inducers, ginsenoside Rb 1 facilitated adipogenesis of 3T3-L1 preadipocytes in a dose-dependent manner; 10 μM Rb 1 increased lipid accumulation by about 56%. Treatment of differentiating adipocytes with 10 μM Rb 1 increased the expression of mRNA and protein of PPARγ 2 and C/EBPα, as well as mRNA of ap2, one of their target genes. After the treatment of differentiating adipocytes with Rb 1, basal and insulin-mediated glucose uptake was significantly augmented, accompanied by the up-regulation of mRNA and protein level of GLUT4, but not of GLUT1. In addition, ginsenoside Rb 1 also inhibited the proliferation of preconfluent 3T3-L1 preadipocytes. Our data indicate that anti-diabetic and insulin-sensitizing activities of ginsenosides, at least in part, are involved in the enhancing effect on PPARγ2 and C/EBPα expression, hence promoting adipogenesis.