The Molecular Mechanism of Glucocorticoid-Induced Insulin Resistance / 中国医师杂志

ABSTRACT

Objective To explore the effect of glucocorticoid on glucose transport activity and the expression of insulin signaling peptides in the primary cultured rat adipocytes .Methods Isolated rat adipocytes were cultured for 2h,8h,16h and 24h respectively at 5 mmol glucose with dexamethasone (Dex) 0 3?mol. Then the glucose uptake, cellular contents of insulin receptor substrate (IRS) 1/2, phosphatidylinositol 3-kinase 85 subunit (p85) and protein kinase B(PKB)were measured by Western blotting.Results These adipocytes treated with Dex have shown to impair the basal and insulin-induced glucose uptake with a maximum inhibition at 2h and 24h respectively; Dex down-regulated IRS1 protein expression in a time-dependent manner and up-regulated IRS2 content. The cellular p85 and PKB contents were also decreased by Dex. Conclusion Chronic exposure to glucocorticoid can inhibit glucose uptake and induce insulin resistance. The mechanism may be involved in affecting the expression of insulin signaling peptides.