Green tea epigallocatechin gallate inhibits insulin stimulation of adipocyte glucose uptake via the 67-kilodalton laminin receptor and AMP-activated protein kinase pathways

Chi Fen Hsieh, Yi Wei Tsuei, Chi Wei Liu, Chung Cheng Kao, Li Jane Shih, Low Tone Ho, Liang Yi Wu, Chi Peng Wu, Pei Hua Tsai, Hsin Huei Chang, Hui Chen Ku, Yung Hsi Kao

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Insulin and (-)-epigallocatechin gallate (EGCG) are reported to regulate obesity and fat accumulation, respectively. This study investigated the pathways involved in EGCG modulation of insulin-stimulated glucose uptake in 3T3-L1 and C3H10T1/2 adipocytes. EGCG inhibited insulin stimulation of adipocyte glucose uptake in a dose- and time-dependent manner. The concentration of EGCG that decreased insulin-stimulated glucose uptake by 5060% was approximately 510μ M for a period of 2h. At 10μ M, EGCG and gallic acid were more effective than (-)-epicatechin, (-)-epigallocatechin, and (-)-epicatechin 3-gallate. We identified the EGCG receptor [also known as the 67-kDa laminin receptor (67LR)] in fat cells and extended the findings for this study to clarify whether EGCG-induced changes in insulin-stimulated glucose uptake in adipocytes could be mediated through the 67LR. Pretreatment of adipocytes with a 67LR antibody, but not normal rabbit immunoglobulin, prevented the effects of EGCG on insulin-increased glucose uptake. This suggests that the 67LR mediates the effect of EGCG on insulin-stimulated glucose uptake in adipocytes. Moreover, pretreatment with an AMP-activated protein kinase (AMPK) inhibitor, such as compound C, but not with a glutathione (GSH) activator, such as N-acetyl-L-cysteine (NAC), blocked the antiinsulin effect of EGCG on adipocyte glucose uptake. These data suggest that EGCG exerts its anti-insulin action on adipocyte glucose uptake via the AMPK, but not the GSH, pathway. The results of this study possibly support that EGCG mediates fat content.

Original languageEnglish
Pages (from-to)1694-1698
Number of pages5
JournalPlanta Medica
Volume76
Issue number15
DOIs
StatePublished - 2010

Keywords

  • Camellia sinensis
  • epigallocatechin 3gallate
  • glucose uptake
  • green tea
  • insulin
  • Theaceae

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