title: 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: Division of Endocrinology, Diabetes and Metabolism, Hematology, Rheumatology (Second Department of Internal Medicine), Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan.
authors: Chisayo
authors: C
authors: Kozuka
authors: Kouichi
authors: K
authors: Yabiku
authors: Sumito
authors: S
authors: Sunagawa
authors: Rei
authors: R
authors: Ueda
authors: Shin-Ichiro
authors: S
authors: Taira
authors: Hiroyuki
authors: H
authors: Ohshiro
authors: Tomomi
authors: T
authors: Ikema
authors: Ken
authors: K
authors: Yamakawa
authors: Moritake
authors: M
authors: Higa
authors: Hideaki
authors: H
authors: Tanaka
authors: Chitoshi
authors: C
authors: Takayama
authors: Masayuki
authors: M
authors: Matsushita
authors: Seiichi
authors: S
authors: Oyadomari
authors: Michio
authors: M
authors: Shimabukuro
authors: Hiroaki
authors: H
authors: Masuzaki
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001835:Body Weight / Q000187:drug effects; D002478:Cells, Cultured; D059305:Diet, High-Fat; D004435:Eating / Q000187:drug effects; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D005518:Food Preferences / Q000187:drug effects*; D005951:Glucose Tolerance Test; D051379:Mice; D008810:Mice, Inbred C57BL; D012275:Oryza / Q000378:metabolism*; D010654:Phenylbutyrates / Q000494:pharmacology; D010666:Phenylpropionates / Q000494:pharmacology*; D060888:Real-Time Polymerase Chain Reaction; D014280:Triglycerides / Q000378:metabolism
chemical_list: D010654:Phenylbutyrates; D010666:Phenylpropionates; D014280:Triglycerides; C075773:4-phenylbutyric acid; C013172:gamma-oryzanol