Medycyna Wet. 63 (1), 113-117, 2007
Noszczyk-Nowak A., Pasławska U., Zyœko D., Gajek J., Nicpoń J., Rabczyński J., Skrzypczak P.
Cardiac hypertrophy induced by administration oral of L-thyroxine in growing pigs
The aim of the experiment was to evaluate the influence of oral administration of L-thyroxine on the heart. The research material included 8 pigs of the polska bia³a zwis³oucha breed. The experimental hyperthyroidism was induced by oral administration of L-thyroxine at a dose 20 µg/kg b.w. in 4 pigs. The echocardiography examination was carried out 3 times in each pig: before hyperthyroidism outset and twice in hyperthyroxinemia. Through echocardiographic examination a statistically significant increase in LWd was stated. An increase in IVSd, decrease in LVd and a statistically significant increase in relative wall thickness and left ventricular mass in the group of pigs administered L-tyroxine was observed. A statistically significant decrease in SF connected with an increase in the left ventricle wall thickness occurred as well. The performed autopsy revealed an increased thickness of the right and left heart ventricles in swine with the experimental hyperthyroidism. It was stated that hyperthyroxinemia induces heart muscle hypertrophy which concerns mainly the ventricular muscles. Observed secondary hypertrophic cardiomyopathy may be the consequence of hyperthyroxinemia.
Keywords: pig, hyperthyroxinemia, echocardiography