Brown rice and its component, γ-oryzanol, attenuate the preference for high-fat diet by decreasing hypothalamic endoplasmic reticulum stress in mice.

Abstract

Brown rice is known to improve glucose intolerance and prevent the onset of diabetes. However, the underlying mechanisms remain obscure. In the current study, we investigated the effect of brown rice and its major component, γ-oryzanol (Orz), on feeding behavior and fuel homeostasis in mice. When mice were allowed free access to a brown rice-containing chow diet (CD) and a high-fat diet (HFD), they significantly preferred CD to HFD. To reduce hypothalamic endoplasmic reticulum (ER) stress on an HFD, mice were administered with 4-phenylbutyric acid, a chemical chaperone, which caused them to prefer the CD. Notably, oral administration of Orz, a mixture of major bioactive components in brown rice, also improved glucose intolerance and attenuated hypothalamic ER stress in mice fed the HFD. In murine primary neuronal cells, Orz attenuated the tunicamycin-induced ER stress. In luciferase reporter assays in human embryonic kidney 293 cells, Orz suppressed the activation of ER stress-responsive cis-acting elements and unfolded protein response element, suggesting that Orz acts as a chemical chaperone in viable cells. Collectively, the current study is the first demonstration that brown rice and Orz improve glucose metabolism, reduce hypothalamic ER stress, and, consequently, attenuate the preference for dietary fat in mice fed an HFD.

• Authors: Chisayo Kozuka, Kouichi Yabiku, Sumito Sunagawa, Rei Ueda, Shin-Ichiro Taira, Hiroyuki Ohshiro, Tomomi Ikema, Ken Yamakawa, Moritake Higa, Hideaki Tanaka, Chitoshi Takayama, Masayuki Matsushita, Seiichi Oyadomari, Michio Shimabukuro, Hiroaki Masuzaki
• Journal: Diabetes (Diabetes) Vol. 61 Issue 12 Pg. 3084-93 (Dec 2012) ISSN: 1939-327X [Electronic] United States
• PMID: 22826028 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Phenylbutyrates
• Phenylpropionates
• Triglycerides
• 4-phenylbutyric acid
• gamma-oryzanol

Topics

• Animals
• Blotting, Western
• Body Weight (drug effects)
• Cells, Cultured
• Diet, High-Fat
• Eating (drug effects)
• Endoplasmic Reticulum Stress (drug effects)
• Food Preferences (drug effects)
• Glucose Tolerance Test
• Mice
• Mice, Inbred C57BL
• Oryza (metabolism)
• Phenylbutyrates (pharmacology)
• Phenylpropionates (pharmacology)
• Real-Time Polymerase Chain Reaction
• Triglycerides (metabolism)