(AG) is a Korean traditional plant that grows in Ulleungdo Island, Republic of Korea. for the inhibition of excess fat accumulation. As shown in Physique 1, the number and size of cytosolic lipid droplets markedly decreased (Physique 1(a)), and reduction in excess fat accumulation, dependent on concentration, was observed (Physique 1(b)). Intracellular TG was analyzed with the AdipoRed assay. On day 2, the accumulation of TG in the differentiated cells was comparable to that in the AG-treated cells (Physique 1(c)). After 8 days, the AG-treated differentiated cells showed significantly lower TG levels, exhibiting a dose-dependent switch, than those in the untreated differentiated cells (Physique 1(d)). To assess cellular capacity to produce adipocyte-derived hormones, we monitored the expression of leptin, a well-documented hormone with anti-diabetic properties, in cells of adipocyte lineage. Significant suppression of leptin protein secretion was observed in 3T3-L1 cells by the treatment with AG (Physique 1(e)). Physique 1 Effects of AG on adipocyte differentiation. (a) Fat droplets in adipocyte differentiated for 8 days with or without AG were stained with oil reddish dye. (b) Relative lipid accumulation was calculated. Troglitazone was used as a positive control. Accumulation … 3.2. AG Regulation of the Expression of Adipogenic Genes in Adipocytes The differentiation of adipocytes from preadipocytes is usually correlated with the expression of adipogenic genes. PPARwas evidently reduced in the epididymal tissue taken from AG-treated HFD mice. The expression of C/EBPis a ligand-activated transcription factor that plays an important role in the regulation of obesity. It exists as a heterodimer with another nuclear hormone receptor, retinoid X receptor, or RXR to bind to DNA, and it is actively involved in adipogenesis [23]. Adipocyte differentiation provokes PPARactivity, and it transfers hormonal activation to its target genes such as PD0325901 C/EBPand LPL [19, 24]. Although C/EBPis induced by PPAR[25]. Despite its role as a target gene of PPARacts in a positive-feedback loop to express PPARand other adipogenic-related genes. It maintains an enhanced differentiated state [26]. SREBP1c also has a profound effect on adipogenesis; it stimulates the expression of many lipogenic genes and regulates fatty acid and glucose metabolism [27]. Furthermore, it has been suggested that SREBP1c is usually correlated with the production of an endogenous PPARligand that reinforces PPARactivity and, for this reason, PPARis a target gene of SREBP1c [28, 29]. Considering the significance of these factors that take a leading position in adipogenesis, AG seems to suppress adipocyte differentiation by blocking PPAR[7]. Because PPARdirectly regulates LXRand LXR form a positive-feedback relation in adipocyte differentiation [31]. In this study, AG decreased LXR levels in 3T3-L1 cells and in epididymal adipose tissues. Leptin, a hormone secreted largely by adipose tissue to maintain body excess fat, regulates food intake and energy expenditure through its action around the hypothalamus. When the level of body fat mass decreases, plasma leptin levels fall, stimulating appetite and suppressing PD0325901 energy expenditure until excess fat mass is usually restored. Conversely, when excess fat mass increases, levels of leptin increase and suppress appetite until excess weight is usually lost. Thus adipose tissue mass seems to be under PD0325901 the control of leptin [32]. In brief, an activated leptin gene links to a state of obesity. In our results, the expression of the leptin gene was decreased by AG, apparently signifying that AG attenuates weight gain and excess fat accumulation by inhibiting leptin release. Leptin resistance, the hallmark of high-Fat diet induced IgM Isotype Control antibody (APC) obesity model, is usually a phenomenon in which circulating leptin levels decrease in response to target tissues, such as adipose PD0325901 tissue, muscles, liver, and hypothalamus. In most cases, the leptin resistance could be either main or acquired. In human adiposity, although there exit substantial individual differences at some specific levels of body fat, leptin concentrations in the blood circulation are associated with adipose tissue [33]. Therefore, the close correlation between hyperleptinemia and body weight has resulted in acknowledgement of leptin resistance as a cause of obesity. In our present study, leptin resistance is developed by the administration of a high-fat diet. Subsequently, treatment with AG decreased leptin gene level, and this means that AG may ameliorate leptin resistance. In our experiment, we used a small amount of the AG extract at doses of 1% and 5% AG (w/w in HFD). We usually use 10C20% doses for evaluating the.