Effect of mifepristone on glucocorticoid receptor gene expression in the liver of rats with streptozotocin-induced diabetes.

The effects of mifepristone on activity of the adrenocortical system, expression of glucocorticoid receptor gene, and tyrosine aminotransferase activity in the liver were studied in rats with streptozotocin-induced diabetes. Administration of glucocorticoid receptor blocker mifepristone to rats without diabetes was followed by a 1.9-fold increase in serum corticosterone concentration and a 1.2-fold increase in tyrosine aminotransferase activity in the liver in comparison with the baseline values. In rats with streptozotocin-induced diabetes, mifepristone produced a less pronounced increase in the corticosterone concentration (by 1.5 times) and more drastic increase in enzyme activity (by 1.7 times). Mifepristone administration did not change the content of glucocorticoid receptor mRNA in the liver of rats without diabetes, but increase this parameter by 1.4 times in rats with streptozotocin-induced diabetes. The enhanced expression of glucocorticoid receptor gene in the liver of rats with streptozotocin-induced diabetes correlated with increased activity of tyrosine aminotransferase after mifepristone treatment.