Sex steroids enhance insulin receptors and glucose oxidation in Chang liver cells

Background: The present study was designed to assess the effect of sex steroids (testosterone and 17 beta-estradiol) on insulin receptor expression, insulin binding and glucose oxidation in human liver cell line. Methods: Non-malignant Chang liver cells were treated with different concentrations of testosterone and 17 beta-estradiol dissolved in serum free medium for 24 h to identify the effective dose of both steroids for further studies. Cells with 70-80% confluency were challenged with testosterone (0.1 mu mol/1), 17 beta-estradiol (0.1 mu mol/1) and their combination along with insulin as a positive control for 24 h. After the treatment period, insulin receptor mRNA expression, cell surface insulin binding and C-14-glucose oxidation were assessed. Results: Both testosterone and 17 beta-estradiol significantly increased the insulin receptor mRNA expression, cell surface insulin binding and C-14-glucose oxidation compared to basal, but the increase was not at par with the effect of insulin. Compared to individual effects of testosterone and 17 beta-estradiol, their combination significantly increased the glucose oxidation similar to that of insulin. Conclusion: It is concluded from the present study that testosterone and 17 beta-estradiol can directly enhance insulin receptor mRNA expression, insulin binding and glucose oxidation in Chang liver cells and thereby glucose metabolism. (C) 2008 Elsevier B.V. All rights reserved.