Signals in the Activation of Opioid µ-Receptors by Loperamide to Enhance Glucose Uptake into Cultured C<sub>2</sub>C<sub>12</sub>Cells

Im, Liu; Ss, Liou; Wc, Chen; Pf, Chen; Jt, Cheng

doi:10.1055/s-2004-814449

Cited by 14 publications

(1 citation statement)

References 17 publications

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“…Moreover, chelerythrine and GF 109203X diminished the stimulatory effect of β -endorphin on radioactive glucose uptake into isolated soleus muscle at a concentration sufficient to inhibit PKC [58]. The linkage of MOR and the PLC-PKC pathway in the regulation of glucose uptake is further characterized using the blockade of loperamide-stimulated 2-DG uptake in C 2 C 12 cells by the inhibitors specific for PLC or PKC [76]. The data suggest that activation of MOR may increase glucose uptake in peripheral tissues via the PLC-PKC pathway to lower plasma glucose in diabetic rats lacking insulin.…”

Section: Peripheral Mor Activation Participates In the Plasma Glucmentioning

confidence: 99%

Mediation of Endogenous β‐Endorphin in the Plasma Glucose‐Lowering Action of Herbal Products Observed in Type 1‐Like Diabetic Rats

Liu

Cheng

2010

Evidence-Based Complementary and Alternative Medicine

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Recently, there have been advances in the development of new substances effective in managing diabetic disorders. Opioid receptors couple multiple systems to result in various biological effects, although opioids are best known for analgesia. In the present review, we used our recent data to describe the advance in plasma glucose-lowering action of herbal products, especially the mediation of β-endorphin in glucose homeostasis of insulin-deficient diabetes. In type 1-like streptozotocin-induced diabetic rats, we identified many products purified from herbs that show a dose-dependent plasma glucose-lowering action. Increase in β-endorphin secretion from the adrenal gland may activate peripheral opioid μ-receptors (MOR) to enhance the expression of muscle glucose transporters and/or to reduce hepatic gluconeogenesis at the gene level, thereby leading to improved glucose utilization in peripheral tissues for amelioration of severe hyperglycemia. It has also been observed that stimulation of α 1-adrenoceptors (α 1-ARs) in the adrenal gland by some herbal products is responsible for the increase in β-endorphin secretion via a phospholipase C-protein kinase dependent pathway. However, an increase in β-endorphin secretion from the adrenal gland by herbal products can function via another receptor. New insights into the mediation of endogenous β-endorphin activation of peripheral MOR by herbal products for regulation of glucose homeostasis without the presence of insulin have been established. Therefore, an increase in β-endorphin secretion and/or direct stimulation of peripheral MOR via an insulin-independent action might serve as the potential target for development of a therapeutic agent or promising adjuvant in intensive plasma glucose control.

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Section: Peripheral Mor Activation Participates In the Plasma Glucmentioning

confidence: 99%

Mediation of Endogenous β‐Endorphin in the Plasma Glucose‐Lowering Action of Herbal Products Observed in Type 1‐Like Diabetic Rats

Liu

Cheng

2010

Evidence-Based Complementary and Alternative Medicine

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Mediation of ?-endorphin in exercise-induced improvement in insulin resistance in obese Zucker rats

Su¹,

Chang

Pai³

et al. 2005

Diabetes Metab. Res. Rev.

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Activation of opioid μ-receptors by loperamide to improve interleukin-6-induced inhibition of insulin signals in myoblast C2C12 cells

Tzeng

Liu²

2005

Diabetologia

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Aims/hypothesis: This study investigated the role of opioid μ-receptor activation in the improvement of insulin resistance. Methods: Myoblast C 2 C 12 cells were cultured with IL-6 to induce insulin resistance. Radioactive 2-deoxyglucose (2-DG) uptake was used to evaluate the effect of loperamide on insulin-stimulated glucose utilisation. Protein expression and phosphorylation in insulinsignalling pathways were detected by immunoblotting. Results: The insulin-stimulated 2-DG uptake was reduced by IL-6. Loperamide reversed this uptake, and the uptake was inhibited by blockade of opioid μ-receptors. Insulin resistance induced by IL-6 was associated with impaired expression of the insulin receptor (IR), IR tyrosine autophosphorylation, IRS-1 protein content and IRS-1 tyrosine phosphorylation. Also, an attenuated p85 regulatory subunit of phosphatidylinositol 3-kinase, Akt serine phosphorylation and the protein of glucose transporter subtype 4 were observed in insulin resistance. Loperamide reversed IL-6-induced decrement of these insulin signals. Conclusions/interpretation: Opioid μ-receptor activation may improve IL-6-induced insulin resistance through modulation of insulin signals to reverse the responsiveness of insulin. This provides a new target in the treatment of insulin resistance.

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Signals in the Activation of Opioid µ-Receptors by Loperamide to Enhance Glucose Uptake into Cultured C₂C₁₂Cells

Cited by 14 publications

References 17 publications

Mediation of Endogenous β‐Endorphin in the Plasma Glucose‐Lowering Action of Herbal Products Observed in Type 1‐Like Diabetic Rats

Mediation of Endogenous β‐Endorphin in the Plasma Glucose‐Lowering Action of Herbal Products Observed in Type 1‐Like Diabetic Rats

Mediation of ?-endorphin in exercise-induced improvement in insulin resistance in obese Zucker rats

Activation of opioid μ-receptors by loperamide to improve interleukin-6-induced inhibition of insulin signals in myoblast C2C12 cells

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Signals in the Activation of Opioid µ-Receptors by Loperamide to Enhance Glucose Uptake into Cultured C2C12Cells

Cited by 14 publications

References 17 publications

Mediation of Endogenous β‐Endorphin in the Plasma Glucose‐Lowering Action of Herbal Products Observed in Type 1‐Like Diabetic Rats

Mediation of Endogenous β‐Endorphin in the Plasma Glucose‐Lowering Action of Herbal Products Observed in Type 1‐Like Diabetic Rats

Mediation of ?-endorphin in exercise-induced improvement in insulin resistance in obese Zucker rats

Activation of opioid μ-receptors by loperamide to improve interleukin-6-induced inhibition of insulin signals in myoblast C2C12 cells

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Product

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Signals in the Activation of Opioid µ-Receptors by Loperamide to Enhance Glucose Uptake into Cultured C₂C₁₂Cells