Effect of hydrocortisone and dexamethasone on xylose uptake by isolated rat soleus muscle

To determine the effects of glucocorticoids on sugar uptake, xylose uptake by isolated rat soleus muscle of bilaterally adrenalectomized animals was studied. The results indicate that in vitro addition of 10-4 M hydrocortisone, dexamethasone or hydrocortisone sodium succinate had no inhibitory effect on basal xylose uptake. In the presence of both low and high medium insulin, the above steroids failed to inhibit insulin-stimulated uptake. When the concentration of hydrocortisone sodium succinate was increased to 10-2 M, insulinstimulated uptake was decreased. The results thus indicate that glucocorticoids at concentrations observed under physiological or pathological conditions do not inhibit basal or insulin-stimulated sugar uptake.