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Effects of amiodarone and thyroid dysfunction on myocardial calcium, serum calcium and thyroid hormones in the rat
Author(s) -
Gammage M.D.,
Franklyn J.A.,
Logan S.D.
Publication year - 1987
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1987.tb11332.x
Subject(s) - medicine , amiodarone , endocrinology , euthyroid , triiodothyronine , calcium , thyroid , hormone , calcium metabolism , atrial fibrillation
1 Myocardial calcium content was found to be elevated and serum calcium reduced in hypothyroid rats. 2 Treatment of rats with amiodarone at either 30 mg kg −1 or 150 mg kg −1 daily did not result in any significant changes in myocardial or serum calcium. 3 The administration of amiodarone to hypothyroid rats attenuated the changes in serum but not myocardial calcium, suggesting that amiodarone may exert a thyroid hormone‐like effect in the hypothyroid state. 4 The administration of amiodarone to thyroid hormone‐treated rats resulted in attenuation of the effects on serum calcium and calculated intracellular calcium; this was consistent with an antagonistic interaction between amiodarone and thyroid hormones. 5 Administration of amiodarone resulted in significant changes in circulating thyroid hormone levels in the rat; triiodothyronine was reduced and basal thyrotrophin elevated compared to euthyroid controls. Serum thyroxine was not changed; this is in contrast to the effects in man. 6 Amiodarone does not exert its anti‐arrhythmic action via changes in total myocardial calcium content in the euthyroid rat; nonetheless the described interactions between the drug and thyroid hormones may be involved in its mechanism of action.