Hypothyroid-like effect of amiodarone in the ventricular myocardium of the rat |
| |
Authors: | Dr. V. Wiegand G. Wagner H. Kreuzer |
| |
Affiliation: | (1) Present address: Department of Cardiology, University of Göttingen, Robert-Koch-Straße 40, D-3400 Göttingen, F.R.G.;(2) Clinical Chemistry, University of Göttingen, (F.R.G.) |
| |
Abstract: | Summary Due to the similar electrophysiological effects of amiodarone and hypothyroidism in the myocardium, the induction of a local hypothyroid state has been proposed as the mechanism of action of amiodarone. To examine this hypothesis we have studied the influence of amiodarone on the distribution of ventricular isomyosins — a sensitive parameter of the thyroid state in the rat heart — and the effects of amiodarone on 3,5,3-triiodothyronine (T3) myocardial nuclear receptor binding in vivo.Amiodarone induced a dosage-dependent redistribution of isomyosins similar to hypothyroidism, while simultaneously inducing a low T3 syndrome at the higher dose level. In hypothyroid rats, which were pretreated with amiodarone, substitution of T3 (2 g/100 g) led to a complete reversal of the myosin pattern not differing from control hypothyroid rats which were only given T3; the effect of T3 (0.5 g/100 g) was however partially inhibited by amiodarone. Nuclear receptor binding of T3 determined in hypothyroid rats in vivo was unaffected by amiodarone.We conclude that amiodarone induces a hypothyroid-like state in the ventricular myocardium of rats by inhibiting the action of T3 — an effect which cannot be attributed to an antagonism at the T3 nuclear receptor level. |
| |
Keywords: | amiodarone isomyosins myocardium T3 nuclear receptor rat |
本文献已被 SpringerLink 等数据库收录! |
|