Effects of high glucose on phosphorylations of insulin signaling proteins in rat adipocytes / 中华内分泌代谢杂志

ABSTRACT

Objective To explore the effects of high glucose on glucose transport activity, and phosphorylationandexpressionofinsulinsignalingproteins in primary cultured rat adipocytes. Methods Isolated rat adipocytes were cultured at different glucose concentrations (5, 10, 15, 25 mmol/L) for 24 h. Then the glucose uptake, the phosphorylations of insulin receptor (IR), insulin receptor substrate (IRS) 1 and 2 and protein kinase B (PKB) as well as the protein expressions of IRS1, IRS2, p85 subunit of phosphatitylinositol 3 kinase (p85) and PKB were measured. Results These adipocytes treated with different high glucose showed the impairment of the basal and insulin induced increase in glucose uptake and significant decrease of IR, IRS1 and PKB phosphorylations as well as IRS1 protein expression, but up regulation of IRS2 protein expression. p85 and PKB contents and IRS2 phosphorylation were unaffected. Conclusion The exposure to high glucose inhibits glucose uptake and induces insulin resistance in adipocyte. The mechanism may be involved in affecting the multiple step phosphorylations and the expressions of insulin signaling proteins.