Horm Metab Res 1990; 22(2): 85-89
DOI: 10.1055/s-2007-1004857
Originals Basic

© Georg Thieme Verlag, Stuttgart · New York

Amiodarone Reduces the Effect of T3 on Beta Adrenergic Receptor Density in Rat Heart

R. Hartong1 , W. M. Wiersinga1 , T. A. Plomp2
  • 1Department of Endocrinology, University of Amsterdam, Amsterdam
  • 2Netherlands Institute for Drugs and Doping Research, State University of Utrecht, Utrecht, The Netherlands
Further Information

Publication History

1988

1989

Publication Date:
14 March 2008 (online)

Summary

The effect of injection of 1 mg/kg triiodothyronine on cardiac β-adrenoceptor state was investigated in hypothyroid rats and compared to the effect in hypothyroid rats pretreated with amiodarone (200 mg/kg/day for 8 days). The Kd values of iodocyanopindolol binding to the β-receptors were not influenced by either T3 injection or by amiodarone treatment. In the absence of amiodarone, injection of triiodothyronine resulted in a small decrease in receptor density at 6 hr, followed by an increase at 24 hr. Rats treated with amiodarone showed a similar response pattern to hormone injection (i. e. a small decrease in receptor density at 6 hr, followed by an increase at 24 hr), but the amplitude of the response was significantly reduced. Moreover, in vehicle injected rats amiodarone treatment resulted in a decrease in receptor density when rats were mildly hypothyroid, but not when rats were severely hypothyroid. It is concluded that amiodarone interferes (directly or indirectly) with thyroid hormone action in the heart.