title: Oral administration of γ-aminobutyric acid and γ-oryzanol prevents stress-induced hypoadiponectinemia.
abstract: Metabolic syndrome is a cluster of risk factors including insulin resistance and type 2 diabetes and is found to associate partly with chronic stress at work in human. Adiponectin circulates in mammal blood mainly as a low molecular weight (LMW) trimer, hexamer, and a high molecular weight (HMW) multimers. Low circulating levels of adiponectin are related to metabolic syndrome. We have then investigated the influence of immobilization stress on plasma adiponectin concentrations in mice. Relative LMW and HMW adiponectin levels were markedly reduced by immobilization stress (0.66±0.07 and 0.59±0.06 after 102 h, respectively), significantly different from the control values (p<0.01 and 0.05, respectively). γ-Aminobutyric acid (GABA) and γ-oryzanol abundantly contained in germinated brown rice have some physiological functions. We further investigated the effect of GABA, γ-oryzanol, GABA plus γ-oryzanol on adiponectin levels in mice subjected to immobilization stress. GABA and γ-oryzanol significantly increased the relative LMW and HMW adiponectin levels under immobilization stress (1.10±0.11 and 0.99±0.19 after 102 h, respectively, for GABA; 1.08±0.17 and 1.15±0.17 after 102 h, respectively, for γ-oryzanol). Additionally, the co-administration of GABA and γ-oryzanol also increased both relative LMW and HMW adiponectin levels (1.02±0.07 and 0.99±0.10 after 102 h, respectively) and was effective in an earlier phase from 30 to 54 h. The results indicate that the co-administration of GABA and γ-oryzanol might be effective in preventing stress-induced hypoadiponectinemia in mice and be also a promising tool for improving metabolic syndrome aggravated by chronic stress.
authors.affiliation: Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Tokyo, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Ohara
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kiyotani
authors.forename: Asako
authors.initials: A
authors.lastname: Uchida
authors.forename: Reiko
authors.initials: R
authors.lastname: Nagasaka
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Maehara
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Kanemoto
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Hori
authors.forename: Hideki
authors.initials: H
authors.lastname: Ushio
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000284:Administration, Oral; D000818:Animals; D019440:Anti-Obesity Agents / Q000494:pharmacology; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood* / Q000188:drug therapy*; D051379:Mice; D008810:Mice, Inbred C57BL; D012275:Oryza / Q000737:chemistry; D010666:Phenylpropionates / Q000494:pharmacology*; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
chemical_list: D052242:Adiponectin; D019440:Anti-Obesity Agents; D010666:Phenylpropionates; D010936:Plant Extracts; D005680:gamma-Aminobutyric Acid; C013172:gamma-oryzanol