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High-dose Resveratrol Inhibits Insulin Signaling Pathway in 3T3-L1 Adipocytes.

Lee H, Kim JW - J Lifestyle Med (2013)

Bottom Line: We treated differentiated 3T3-L1 adipocytes with resveratrol to observe whether resveratrol is effective at reducing lipid accumulation.Resveratrol treatment after mitotic clonal expansion resulted in decreased lipid accumulation accompanied by reduced fatty acid synthase expression.The results also provide information about in vivo administration dosages and may explain the discrepancy between in vitro and in vivo effects of resveratrol.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Institute of Genetic Science ; Brain Korea 21 Project for Medical Science.

ABSTRACT

Background: Insulin resistance is a major factor in the development of metabolic syndrome and is associated with central obesity and glucose intolerance. Resveratrol, a polyphenol found in fruits, has been shown to improve metabolic conditions. Although it has been widely studied how resveratrol affects metabolism, little is known about how resveratrol regulates lipogenesis with insulin signaling in 3T3-L1 adipocytes.

Methods: We treated differentiated 3T3-L1 adipocytes with resveratrol to observe whether resveratrol is effective at reducing lipid accumulation.

Results: Resveratrol treatment after mitotic clonal expansion resulted in decreased lipid accumulation accompanied by reduced fatty acid synthase expression. Decreased glucose uptake was observed with inhibited GLUT4 translocation in cells treated with 100 μM resveratrol, suggesting that high doses of resveratrol block insulin signaling in adipocytes. Insulin-stimulated Akt phosphorylation is also dose-dependently reduced with resveratrol treatment. Interestingly, Akt phosphorylation is upregulated when cells are treated with long-term low doses of resveratrol, suggesting that only low doses of resveratrol improve metabolic conditions.

Conclusion: High doses of resveratrol block the insulin signaling pathway, thereby reducing glucose uptake and lipid accumulation in vitro. The results also provide information about in vivo administration dosages and may explain the discrepancy between in vitro and in vivo effects of resveratrol.

No MeSH data available.


Related in: MedlinePlus

Resveratrol inhibits insulin signaling pathway in 3T3-L1 adipocytes. 3T3-L1 cells were differentiated into adipocytes as described in Materials and Methods. (A) After 8 days of differentiation, 3T3-L1 cells were pretreated with or without 50 μM resveratrol (RSV 50) or 100 μM resveratrol (RSV 100) for 3 h and then exposed to 100 nM insulin for 20 min. Total cell extracts were prepared at the indicated times for Western blot analyses. (B) Confluent cells were pretreated with or without 50 μM resveratrol (RSV 50) or 100 μM resveratrol (RSV 100) for 3 h or 16 h and then exposed to 100 nM insulin for 20 min. Total cell extracts were prepared at the indicated times for Western blot analyses.
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f3-jlm-03-41: Resveratrol inhibits insulin signaling pathway in 3T3-L1 adipocytes. 3T3-L1 cells were differentiated into adipocytes as described in Materials and Methods. (A) After 8 days of differentiation, 3T3-L1 cells were pretreated with or without 50 μM resveratrol (RSV 50) or 100 μM resveratrol (RSV 100) for 3 h and then exposed to 100 nM insulin for 20 min. Total cell extracts were prepared at the indicated times for Western blot analyses. (B) Confluent cells were pretreated with or without 50 μM resveratrol (RSV 50) or 100 μM resveratrol (RSV 100) for 3 h or 16 h and then exposed to 100 nM insulin for 20 min. Total cell extracts were prepared at the indicated times for Western blot analyses.

Mentions: It has been previously demonstrated that Akt signaling is linked to the translocation of GLUT4 to the plasma membrane, resulting in the stimulation of glucose uptake by insulin [22], and leading to activation of mammalian target of rapamycin (mTOR). To determine the effect of resveratrol on insulin signaling, 3T3-L1 adipocytes were pre-treated with or without resveratrol in the short-term (3 h) or long-term (16 h) before insulin stimulation. As a result, a short-term treatment of resveratrol repressed insulin signaling by decreasing Akt phosphorylation and inhibiting the kinase activity of mTOR (Fig. 3A). Long-term resveratrol treatment had a different effect on the phosphorylation of Akt (Fig. 3B). Akt phosphorylation was gradually increased in a dose-dependent manner (1–50 μM), but then decreased at high doses (100 μM). The protein of SirT1 was not affected by resveratrol (Fig. 3A). These results suggest that short-term high doses of resveratrol cause down-regulation of Akt and mTOR on insulin signaling and will not improve insulin sensitivity. The results also show that long-term treatment with low doses of resveratrol may help control metabolic syndrome.


High-dose Resveratrol Inhibits Insulin Signaling Pathway in 3T3-L1 Adipocytes.

Lee H, Kim JW - J Lifestyle Med (2013)

Resveratrol inhibits insulin signaling pathway in 3T3-L1 adipocytes. 3T3-L1 cells were differentiated into adipocytes as described in Materials and Methods. (A) After 8 days of differentiation, 3T3-L1 cells were pretreated with or without 50 μM resveratrol (RSV 50) or 100 μM resveratrol (RSV 100) for 3 h and then exposed to 100 nM insulin for 20 min. Total cell extracts were prepared at the indicated times for Western blot analyses. (B) Confluent cells were pretreated with or without 50 μM resveratrol (RSV 50) or 100 μM resveratrol (RSV 100) for 3 h or 16 h and then exposed to 100 nM insulin for 20 min. Total cell extracts were prepared at the indicated times for Western blot analyses.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390751&req=5

f3-jlm-03-41: Resveratrol inhibits insulin signaling pathway in 3T3-L1 adipocytes. 3T3-L1 cells were differentiated into adipocytes as described in Materials and Methods. (A) After 8 days of differentiation, 3T3-L1 cells were pretreated with or without 50 μM resveratrol (RSV 50) or 100 μM resveratrol (RSV 100) for 3 h and then exposed to 100 nM insulin for 20 min. Total cell extracts were prepared at the indicated times for Western blot analyses. (B) Confluent cells were pretreated with or without 50 μM resveratrol (RSV 50) or 100 μM resveratrol (RSV 100) for 3 h or 16 h and then exposed to 100 nM insulin for 20 min. Total cell extracts were prepared at the indicated times for Western blot analyses.
Mentions: It has been previously demonstrated that Akt signaling is linked to the translocation of GLUT4 to the plasma membrane, resulting in the stimulation of glucose uptake by insulin [22], and leading to activation of mammalian target of rapamycin (mTOR). To determine the effect of resveratrol on insulin signaling, 3T3-L1 adipocytes were pre-treated with or without resveratrol in the short-term (3 h) or long-term (16 h) before insulin stimulation. As a result, a short-term treatment of resveratrol repressed insulin signaling by decreasing Akt phosphorylation and inhibiting the kinase activity of mTOR (Fig. 3A). Long-term resveratrol treatment had a different effect on the phosphorylation of Akt (Fig. 3B). Akt phosphorylation was gradually increased in a dose-dependent manner (1–50 μM), but then decreased at high doses (100 μM). The protein of SirT1 was not affected by resveratrol (Fig. 3A). These results suggest that short-term high doses of resveratrol cause down-regulation of Akt and mTOR on insulin signaling and will not improve insulin sensitivity. The results also show that long-term treatment with low doses of resveratrol may help control metabolic syndrome.

Bottom Line: We treated differentiated 3T3-L1 adipocytes with resveratrol to observe whether resveratrol is effective at reducing lipid accumulation.Resveratrol treatment after mitotic clonal expansion resulted in decreased lipid accumulation accompanied by reduced fatty acid synthase expression.The results also provide information about in vivo administration dosages and may explain the discrepancy between in vitro and in vivo effects of resveratrol.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Institute of Genetic Science ; Brain Korea 21 Project for Medical Science.

ABSTRACT

Background: Insulin resistance is a major factor in the development of metabolic syndrome and is associated with central obesity and glucose intolerance. Resveratrol, a polyphenol found in fruits, has been shown to improve metabolic conditions. Although it has been widely studied how resveratrol affects metabolism, little is known about how resveratrol regulates lipogenesis with insulin signaling in 3T3-L1 adipocytes.

Methods: We treated differentiated 3T3-L1 adipocytes with resveratrol to observe whether resveratrol is effective at reducing lipid accumulation.

Results: Resveratrol treatment after mitotic clonal expansion resulted in decreased lipid accumulation accompanied by reduced fatty acid synthase expression. Decreased glucose uptake was observed with inhibited GLUT4 translocation in cells treated with 100 μM resveratrol, suggesting that high doses of resveratrol block insulin signaling in adipocytes. Insulin-stimulated Akt phosphorylation is also dose-dependently reduced with resveratrol treatment. Interestingly, Akt phosphorylation is upregulated when cells are treated with long-term low doses of resveratrol, suggesting that only low doses of resveratrol improve metabolic conditions.

Conclusion: High doses of resveratrol block the insulin signaling pathway, thereby reducing glucose uptake and lipid accumulation in vitro. The results also provide information about in vivo administration dosages and may explain the discrepancy between in vitro and in vivo effects of resveratrol.

No MeSH data available.


Related in: MedlinePlus