• The Korean Journal of Physiology and Pharmacology
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• v.20 no.2
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• pp.153-160
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• 2016

The objective was to investigate the hypoglycemic action of catalpol in spontaneous diabetes db/db mice. 40 db/db mice were randomly divided into five groups: model control gourp; db/db plus catalpol 40, 80, 120 mg/kg body wt. groups and db/db plus metformin 250 mg/kg group. Age-matched db/m mice were selected as normal control group. The mice were administered with corresponding drugs or solvent by gavage for 4 weeks. The oral glucose tolerance test was carried out at the end of $3^{rd}$ week. After 4 weeks of treatment, the concentrations of fasting blood glucose (FBG), glycated serum protein (GSP), insulin (INS), triglyceride (TG), total cholesterol (TC) and adiponection (APN) in serum were detected. The protein expressions of phosphorylation-$AMPK{\alpha}$1/2 in liver, phosphorylation-$AMPK{\alpha}$1/2 and glucose transporter-4 (GLUT-4) in skeletal muscle and adipose tissues were detected by western blot. Real time RT-PCR was used to detect the mRNA expressions of acetyl-CoA carboxylase (ACC) and Hydroxymethyl glutaric acid acyl CoA reductase (HMGCR) in liver. Our results showed that catalpol could significantly improve the insulin resistance, decrease the serum concentrations of INS, GSP, TG, and TC. The concentrations of APN in serum, the protein expression of phosphorylation-$AMPK{\alpha}$1/2 in liver, phosphorylation-$AMPK{\alpha}$1/2 and GLUT-4 in peripheral tissue were increased. Catalpol could also down regulate the mRNA expressions of ACC and HMGCR in liver. In conclusion, catalpol ameliorates diabetes in db/db mice. It has benefit effects against lipid/glucose metabolism disorder and insulin resistance. The mechanism may be related to up-regulating the expression of phosphorylation-$AMPK{\alpha}$1/2.

• Molecules and Cells
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• v.41 no.8
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• pp.762-770
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• 2018

Adiponectin, a hormone produced by adipose tissue, is very abundant in plasma, and its anti- and pro-inflammatory effects are reported. However, the mechanisms of these pro- and anti-inflammatory effects are not fully defined. Herein, we evaluated the dual inflammatory response mechanism of adiponectin in macrophages. Short-term globular adiponectin (gAd) treatment induced $I{\kappa}B{\alpha}$ degradation, $NF-{\kappa}B$ nuclear translocation, and $TNF-{\alpha}$ production in RAW 264.7 cells. Polymyxin B pretreatment did not block gAd-induced $I{\kappa}B{\alpha}$ degradation, and heated gAd was unable to degrade $I{\kappa}B{\alpha}$, suggesting that the effects of gAd were not due to endotoxin contamination. gAd activated IKK and Akt, and inhibition of either IKK or Akt by dominant-negative $IKK{\beta}$ ($DN-IKK{\beta}$) or DN-Akt overexpression blocked gAd-induced $I{\kappa}B{\alpha}$ degradation, suggesting that short-term incubation with gAd mediates inflammatory responses by activating the $I{\kappa}B/NF-{\kappa}B$ and PI3K/Akt pathways. Contrastingly, long-term stimulation with gAd induced, upon subsequent stimulation, tolerance to gAd, lipopolysaccharide, and CpG-oligodeoxynucleotide, which is associated with gAd-induced downregulation of IL-receptor-associated kinase-1 (IRAK-1) due to IRAK-1 transcriptional repression. Conclusively, our findings demonstrate that the pro- and anti-inflammatory responses to gAd in innate immune cells are time-dependent, and mediated by the activation of the $I{\kappa}B/NF-{\kappa}B$ pathway, and IRAK-1 downregulation, respectively.