 In a recent animal study assessing Rosiglitazones mode of action on lipids using male Sprague-Dawley rats, serum total, free and HDL cholesterol concentrations were monitored. In rats given Rosiglitazone, serum Triglyceride levels decreased in a dose-dependent manner, dropping to less than 50 of that of the control rats at the highest dose tested 5 mgkgd. Serum glucose concentrations did not change after Rosiglitazone treatment, which is in agreement with previous studies showing that thiazolidinediones do not exert a hypoglycemic action in the normoglycemic, non-diabetic rat. 18 