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Objective: The aim of this study was to evaluate the effects of rice as a carbohydrate source and its molecular mechanisms on insulin resistance induced by a high-fat diet (HFD)., Methods: C57 BL/6 J mice were divided into three groups and were fed a low-fat diet (LFD); a HFD (with 18% fat, 0.5% cholesterol, 51.5% w/w cornstarch and sucrose); or a HFD with rice (HFD-CR, with 18% fat, 0.5% cholesterol and 51.5% w/w rice powder) for 12 wk. In the HFD-CR diet, cooked rice powder was substituted for cornstarch and sucrose in the HFD as a carbohydrate source., Results: HFD-CR-fed mice had significantly lower body weight, blood glucose, insulin and leptin levels and ameliorated glucose responses with decreased homeostasis model assessment-insulin resistance compared with HFD-fed mice. Hepatic mRNA levels of phosphoenolpyruvate carboxykinase and glucose-6-phosphatase were down-regulated in the HFD-CR group. The hypertrophied islet size and the decreased pancreatic mRNA expression of glucose transporter 2 in the HFD group were normalized with cooked rice consumption. Rice promoted glucose uptake by activating AMP-activated protein kinase and downstream glucose transporter 4 in the skeletal muscle., Conclusion: Rice consumption as a carbohydrate source might potentiate improvements in glucose uptake via AMP-activated protein kinase activation and glucose transporter 4 expression in the skeletal muscles, thereby improving insulin sensitivity., (Copyright © 2014 Elsevier Inc. All rights reserved.)

There has been great interest in the browning of fat for the treatment of obesity. Although β-lapachone (BLC) has potential therapeutic effects on obesity, the fat-browning effect and thermogenic capacity of BLC on obesity have never been demonstrated. Here, we showed that BLC stimulated the browning of white adipose tissue (WAT), increased the expression of brown adipocyte-specific genes (e.g., uncoupling protein 1 [UCP1]), decreased body weight gain, and ameliorated metabolic parameters in mice fed a high-fat diet. Consistently, BLC-treated mice showed significantly higher energy expenditure compared with control mice. In vitro, BLC increased the expression of brown adipocyte-specific genes in stromal vascular fraction-differentiated adipocytes. BLC also controlled the expression of miR-382, which led to the upregulation of its direct target, Dio2. Upregulation of miR-382 markedly inhibited the differentiation of adipocytes into beige adipocytes, whereas BLC recovered beige adipocyte differentiation and increased the expression of Dio2 and UCP1. Our findings suggest that the BLC-mediated increase in the browning of WAT and the thermogenic capacity of BAT significantly results in increases in energy expenditure. Browning of WAT by BLC was partially controlled via the regulation of miR-382 targeting Dio2 and may lead to the prevention of diet-induced obesity. [ABSTRACT FROM AUTHOR]

Although rice has been shown to have beneficial health effects, little is known about the effect of rice on hepatic lipid accumulation as a carbohydrate source. This study investigated the effects and mechanism of action of cooked rice on high-fat diet (HF)-induced fat accumulation. The C57BL/6 mice were divided into three groups and fed a normal diet (NOR), HF, or HF with cooked rice (HF-CR) for 12 weeks. The HF-CR-fed mice had significantly lower body weight gains and abdominal fat mass compared with the HF-fed mice. Consuming cooked rice resulted in significantly lower serum total cholesterol, low-density lipoprotein cholesterol, hepatic lipid content, and lipid droplet number and size. Cooked rice consumption also suppressed the HF-induced increase in expression of lipogenic genes, such as sterol regulatory element-binding protein 1c (SREBP-1c), fatty acid synthase (FAS), stearoyl CoA desaturase 1 (SCD-1), peroxisome proliferator-activated receptor gamma (PPAR γ), and CD36. The expression of cholesterol metabolism-related genes, such as acyl-CoA:cholesterol acyltransferase 1 (ACAT1), were also downregulated in the HF-CR-fed mice. Cooked rice may prevent HF-induced fat accumulation by regulating lipid metabolism-related gene expression, and it may be a useful carbohydrate source for preventing nonalcoholic fatty liver disease. [ABSTRACT FROM AUTHOR]