ecdysterone and Liver-Neoplasms

The steroid hormone 20-hydroxyecdysone (20HE) is an essential signaling molecule that modulates molting response in insects and may function as a putative anabolic factor in vertebrate animals, although no mammalian 20HE receptor has been identified. Here we show that in H4IIE cell culture, 20HE treatment decreased expression of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase), reduced glucose production, and induced Akt2 phosphorylation sensitive to the phosphoinositide-3 kinase pathway-specific inhibitor LY-294002. Daily oral administration of 20HE (10 mg/kg for 13 wk) ameliorated obesity and insulin resistance in C57BL/6J mice fed a high-fat diet and produced a significant decrease of body weight gain and body fat mass compared with nontreated animals as demonstrated by dual-energy X-ray absorptiometry analysis. In addition, plasma insulin levels and glucose tolerance were significantly lowered by 20HE treatment. These changes were accompanied by the reduced hepatic expression of PEPCK and G6Pase and increased adiponectin production by visceral fat tissue. These studies demonstrate the anti-obesity and anti-diabetic effects of 20HE and begin to elucidate its putative cellular targets both in vitro and in vivo.

Topics: Adiponectin; AMP-Activated Protein Kinases; Animals; Blood Glucose; Body Weight; Carcinoma, Hepatocellular; Cells, Cultured; Dietary Fats; Ecdysterone; Glucose Intolerance; Hyperglycemia; Insulin; Insulin Resistance; Liver Neoplasms; Male; Mice; Mice, Inbred C57BL; Obesity; Phosphatidylinositol 3-Kinases; Rats; STAT1 Transcription Factor

The aims of this study was to investigate whether ecdysterone is able to exert glucose-lowering effect on hepatocytes or stimulate the secretion of insulin. HepG2 cell line was used for glucose consumption (GC) studies. At moderate high glucose concentration (11.1 mmol/L), GC of HepG2 cells was increased by 44% to 77% with ecdysterone 1 x 10(-6) to 1 x 10(-4) mol/L, which was comparable to that with 1 x 10(-3) mol/L metformin. The glucose-lowering effect of ecdysterone decreased as the glucose concentration of medium increased. The maximal potency was reached in the presence of 5.5 mmol/L glucose, and the effect was disappeared as the glucose consumption was increased to 22.2 mmol/L. This effect was independent on insulin concentration, which was similar to that of metformin and was different from that of troglitazone, whose glucose-lowering effect was insulin-dependent. Troglitazone had a better antihyperglycemic potency than metformin when insulin was added. Simultaneously, a significant toxicity of troglitazone to HepG2 cells was observed. betaTC3 cells were not stimulated by ecdysterone, that is, no secretogogue effect of ecdysterone was observed. The results indicate that ecdysterone is able to exert the glucose-lowering effect in hepatocytes which is insulin-independent, but has no effect on insulin release.

Topics: Animals; Cell Line, Tumor; Chromans; Dose-Response Relationship, Drug; Ecdysterone; Glucose; Humans; Hypoglycemic Agents; Insulin; Insulin-Secreting Cells; Liver Neoplasms; Metformin; Mice; Mice, Transgenic; Tetrazolium Salts; Thiazoles; Thiazolidinediones; Troglitazone