Horm Metab Res 2004; 36(2): 119-125
DOI: 10.1055/s-2004-814223
Original Clinical
© Georg Thieme Verlag Stuttgart · New York

Cinnamon Extract Prevents the Insulin Resistance Induced by a High-fructose Diet

B.  Qin 1 , M.  Nagasaki 2 , M.  Ren 3 , G.  Bajotto 1 , Y.  Oshida 1, 2 , Y.  Sato 1, 2
  • 1Department of Sports Medicine, Graduate School of Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
  • 2Research Center of Health, Physical Fitness and Sports, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
  • 3Department of Visual Neuroscience, Graduate School of Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
Further Information

Publication History

Received 16 June 2003

Accepted after revision 18 August 2003

Publication Date:
05 March 2004 (online)

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Abstract

The aim of this study was to determine whether cinnamon extract (CE) would improve the glucose utilization in normal male Wistar rats fed a high-fructose diet (HFD) for three weeks with or without CE added to the drinking water (300 mg/kg/day). In vivo glucose utilization was measured by the euglycemic clamp technique. Further analyses on the possible changes in insulin signaling occurring in skeletal muscle were performed afterwards by Western blotting. At 3 mU/kg/min insulin infusions, the decreased glucose infusion rate (GIR) in HFD-fed rats (60 % of controls, p < 0.01) was improved by CE administration to the same level of controls (normal chow diet) and the improving effect of CE on the GIR of HFD-fed rats was blocked by approximately 50 % by N-monometyl-L-arginine. The same tendency was found during the 30 mU/kg/min insulin infusions. There were no differences in skeletal muscle insulin receptor (IR)-β, IR substrate (IRS)-1, or phosphatidylinositol (PI) 3-kinase protein content in any groups. However, the muscular insulin-stimulated IR-β and IRS-1 tyrosine phosphorylation levels and IRS-1 associated with PI 3-kinase in HFD-fed rats were only 70 ± 9 %, 76 ± 5 %, and 72 ± 6 % of controls (p < 0.05), respectively, and these decreases were significantly improved by CE treatment. These results suggest that early CE administration to HFD-fed rats would prevent the development of insulin resistance at least in part by enhancing insulin signaling and possibly via the NO pathway in skeletal muscle.

References

Y. Sato,M. D., Ph. D. 

Research Center of Health · Physical Fitness and Sports · Nagoya University

Furo-cho · Chikusa-ku · Nagoya 464-8601 · Japan

Phone: + 81 (52) 789 39 62

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Email: ysato@med.nagoya-u.ac.jp