Effects of a new angiotensin type 1 receptor antagonist Ib on the cardiac hypertrophy induced by L-thyroxin in rats

Aim:To study the effect of compound Ⅰb as a new angiotensin type 1 receptor antagonist on the cardiac hypertrophy induced by L-thyroxin in rats.Methods:Rat cardiac hypertrophy was induced by L-thyroxin(0.4 mg/kg·d ×10 d,ip)in rats.The change of cardiac mass index,the Ca-Mg-ATPase activity of cardiac muscle and the LDH and CK that released to the serum were recorded.Results:It was shown that at the dose of 3 mg/kg,commpound(Ⅰb) could improve the cardiac mass index,decreased the Ca-Mg-ATPase activity,significantly decreasing plasma levels of LDH and CK.Electron microscopic examination showed that commpound Ⅰb could improve the structure of cardiac muscle fiber and mitochondria.Cardiac muscle fiber lined up in order and Z line was found to be clear.Conclusion:Results suggest that at the dose of 3 mg/kg,commpound Ⅰb has been shown to be effective against cardiac hypertrophy induced by L-thyroxin in rats.