Changes in vasoreactivity of rat large- and medium-sized arteries induced by hyperthyroidism

Although the excess of thyroid hormones has been found to be associated with many effects on the heart and vasculature, the adaptive changes of various conductive and resistance arteries from different vasculature are largely unknown. In this study, we compared changes in vascular reactivity between aortic and femoral arterial rings in hyperthyroidism rat model. Our results indicate that daily gastric feeding of euthyrox to rat with dosage of 100μg group (H1) or 200μg group (H2) for 25 days was sufficient to induce a thyrotoxicosis. The serum TT3 and TT4 levels, heart weight (HW), body weight (BW), HW/BW ratio and mean diameter of myocardiac cells of the rat were significantly greater (P