Rat heart thyroxine 5'-deiodinase is sensitively depressed by amiodarone.

Journal of Cardiovascular Pharmacology
L S GøtzscheF Andreasen

Abstract

Thyroxine 5'-deiodinase activity (5'-D) is depressed in rat liver by amiodarone. To investigate the possible tardive effect of amiodarone on 5'-D in different tissues, rats were fed amiodarone according to a short-term (group A, 50 mg amiodarone/kg/day for 10 days, total dose 150 mg, n = 16) and long-term regimen (group B, 25 mg amiodarone/kg/day for 20 days, n = 16) (control group, n = 12). Serum, heart, and other tissues were collected for 10 days after drug cessation. Thyroxine (T4), triiodothyronine (T3), amiodarone, and its active metabolite desethylamiodarone (DEA) were determined in serum, and 5'-D was determined in tissues. In group A, amiodarone concentrations in the heart at the time of drug cessation were two times higher than in group B. Higher amiodarone concentrations were also found in other tissues, and DEA was immeasurable in nearly all tissues at all times. In all tissues the amiodarone content declined rapidly. 5'-D was depressed to about 50% of controls (p less than 0.05) in heart throughout the 10-day observation period, despite unmeasureable drug levels (less than 0.03 microgram/g tissue). In contrast, liver and kidney 5'-D normalized after the first day in both treated groups, while muscle 5'-D did not di...Continue Reading

Citations

Jun 1, 1993·Journal of Internal Medicine·J UngerP Denayer
Aug 16, 2016·Thyroid : Official Journal of the American Thyroid Association·Douglas S RossMartin A Walter

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