Inotropic response of the rat heart during development and regression of triiodothyronine-induced hypertrophy.

Journal of Cardiovascular Pharmacology
S LortetA Rossi

Abstract

The inotropic response of rat hearts in vivo was tested by infusion of 2 mmol/kg/h calcium chloride after 14 days of daily 3,3',5-triiodo-L-thyronine (T3) treatment and 14 days following discontinuation of T3 treatment. The hyperthyroid state was characterized by marked cardiac hypertrophy (57% increase in the heart weight/body weight ratio) which was more pronounced in the right ventricle (63% increase). Heart rate and cardiac output index were elevated by 56 and 63%, respectively, and total peripheral resistance was reduced by 40%. Left ventricular systolic pressure (LVSP) was elevated by 15%, the maximal rate of rise in left ventricular pressure (LV dp/dtmax) by 106%, and LV pressure-volume performance by 192%. Right ventricular systolic pressure (RVSP) was elevated by 71%, RV dp/dtmax by 126%, and RV pressure-volume performance by 371%. Intravenous infusion of calcium induced an elevation in heart rate and LV dp/dtmax, the increase of the latter was less pronounced than in the control heart. After 14 days subsequent to discontinuation of T3 treatment, there was a regression of cardiac hypertrophy. However, the LV was still hypertrophied by 12% and the RV by 24%. Heart rate and contractility were normal. The pressure-volume ...Continue Reading

Citations

Feb 7, 2004·Proceedings of the National Academy of Sciences of the United States of America·Ralph V ShohetMasashi Yanagisawa
Apr 1, 1991·Circulation Research·S E CampbellK Rakusan
Jan 6, 2006·FASEB Journal : Official Publication of the Federation of American Societies for Experimental Biology·Giovanna M Ledda-ColumbanoAmedeo Columbano

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