Palmitate Contributes to Insulin Resistance through Downregulation of the Src-Mediated Phosphorylation of Akt in C2C12 Myotubes

Effects of <i>Pollen Typhae</i> Total Flavone On &#946;-Arrestin-2/SRC/ AKT signaling in adipose tissues of Type 2 diabetic rats

“…2). According to the past reports (Luan et al 2009;Feng et al 2012b), β-arrestin-2 protein expression is not changed in adipose tissues of high-fat diet-induced insulin-resistant mice and palmitate-induced insulin-resistant skeletal muscle cells, which is consistent with this study. Because of the key role of β-arrestin-2 in regulating the insulin signaling and an increase in β-arrestin-2 protein expression by PTF, it is likely that PTF has beneficial effects on the β-arrestin-2/Src/Akt signaling.…”

“…2). In palmitate-induced insulin-resistant C2C12 myotubes, insulin-stimulated phosphorylation of Src at Tyr416 and Akt at Thr308/Ser473 is remarkably reduced, with no changes in their total protein expression (Feng et al 2012b). And in aortic strips of type 2 diabetic rats, the phosphorylation of Src and Akt dependent of insulin triggering is also decreased (Nemoto et al 2011).…”

“…In the complex Src phosphorylates Akt on Tyr315/326, which strengthens phosphorylation of Akt at β-arrestin-2 complex, thus improving insulin resistance in animals (Luan et al 2009). Inhibition of Src by PP2 leads to a reduction in phosphorylation of Akt at Thr308/Ser473 in C2C12 myotubes and Hep3B hepatocytes, thereby decreasing glucose uptake and insulin sensitivity (Luan et al 2009;Feng et al 2012b). It is well known that palmitate, a saturated fatty acid, contributes to insulin resistance involving complex mechanisms (Ishii et al 2015).…”

“…It is well known that palmitate, a saturated fatty acid, contributes to insulin resistance involving complex mechanisms (Ishii et al 2015). Moreover, although having no effect on the protein expression of β-arrestin-2, palmitate causes insulin resistance through, at least in part, down-regulating the phosphorylation of Src and Src-mediated phosphorylation of Akt in C2C12 myotubes (Feng et al 2012b). …”

Pollen Typhae total flavone improves insulin resistance in high-fat diet and low-dose streptozotocin-induced type 2 diabetic rats

“…Administration of PTF significantly decreased TG and LDL-c in a dose-dependent manner. We have reported that free fatty acid (palmitate) contributes to insulin resistance 15) and that PTF prevents palmitate-induced impairment of glucose uptake in C2C12 myotubes. 6) Interestingly, rosiglitazone also obviously reduced TG and LDL-c levels, which was in accordance with PTF and the past reports.…”