Rabbit Anti-Human AKT2 (internal) Polyclonal antibody

Obesity, a major health problem worldwide, is a complex multifactorial chronic disease that increases the risk for insulin resistance, type 2 diabetes, coronary heart disease, and hypertension. In this study, we assessed methods to isolate hypaphorine, a potent drug candidate for obesity and insulin resistance. Semi-preparative reversed-phase liquid chromatography (semi-preparative RPLC) was established as a method to separate three compounds, adenosine, l-tryptophan, and hypaphorine, from the crude extracts of Caragana korshinskii Kom. Due to its specific chemical structure, the effect of hypaphorine on differentiation and dexamethasone (DXM) induced insulin resistance of 3T3-L1 cells was investigated. The structures of the three compounds were confirmed by UV, H-1-NMR, and C-13-NMR analysis and compared with published data. The activity results indicated that hypaphorine prevented the differentiation of 3T3-L1 preadipocytes into adipocytes by down-regulating hormone-stimulated protein expression of peroxisome proliferator activated receptor (PPAR) and CCAAT/enhancer binding protein (C/EBP), and their downstream targets, sterol regulatory element binding protein 1 c (SREBP1c) and fatty acid synthase (FAS). Hypaphorine also alleviated DXM-induced insulin resistance in differentiated 3T3-L1 adipocytes via increasing the phosphorylation level of Akt2, a key protein in the insulin signaling pathway. Taken together, we suggest that the method can be applied to large-scale extraction and large-quantity preparation of hypaphorine for treatment of obesity and insulin resistance.

ObjectiveMany overweight/obese subjects appear metabolically healthy with normal invivo insulin sensitivity. Still, they have increased long-term risk of developing type 2 diabetes. We hypothesized that adipose tissue dysfunction involving decreased insulin action in adipocytes is present in apparently healthy overweight/obese subjects. Design/MethodsSubjects with normal metabolic health according to Adult Treatment Panel-III or Framingham risk score criteria were subdivided into 67 lean, 32 overweight and 37 obese according to body mass index. They were compared with 200 obese individuals with metabolic syndrome. Insulin sensitivity and maximum action on inhibition of lipolysis and stimulation of lipogenesis was determined in subcutaneous adipocytes. Gene expression was determined by micro-array and qPCR. DNA methylation was assessed by array, pyrosequencing and reporter assays. ResultsCompared with lean, adipocytes in overweight/obese displayed marked reductions in insulin sensitivity in both antilipolysis and lipogenesis as well as an attenuated maximum lipogenic response. Among these, only antilipolysis sensitivity correlated with whole-body insulin sensitivity. These differences were already evident in the overweight state, were only slightly worse in the unhealthy obese state and were not related to fat cell size. Adipose tissue analyses linked this to reduced expression of the insulin signalling protein AKT2, which associated with increased methylation at regulatory sites in the AKT2 promoter. ConclusionsApparently healthy subjects have severely disturbed adipocyte insulin signalling already in the overweight state which involves epigenetic dysregulation of AKT2. This may constitute an early defect in insulin action that appears even upon modest increases in fat mass.