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Horm Metab Res 1986; 18(2): 110-113
DOI: 10.1055/s-2007-1012244
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© Georg Thieme Verlag, Stuttgart · New York

Effect of Different β-Blocking Drugs and Adrenaline on the Conversion of Thyroxine to Triiodothyronine in Isolated Rat Hepatocytes

Sylvi Aanderud, J. Aarbakke, J. Sundsfjord
  • Department of Medicine, Clinical Pharmacology and Clinical Chemistry, University Hospital of Tromsoe, Tromsoe, Norway
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Publication History

1984

1985

Publication Date:
14 March 2008 (online)

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Summary

The in vitro effect of various selective and non-selective β-blocking drugs and adrenaline on the conversion of thyroxine (T4) to triiodothyronine (T3) was studied in suspensions of isolated rat hepatocytes after 90 min of incubation.

Compared with the untreated controls propranolol caused a dose-related inhibition of the T4 to T3 conversion in conc of 100, 200 and 400 μM. The other β-blocking drugs studied, timolol, oxprenolol, atenolol and metoprolol, were without any effect on this in vitro conversion. Propranolol did not interfere with the cellular association of T4 or the degradation of T4 and T3. Adrenaline 200 μM caused a small decrease of T3 in the medium and a corresponding increase in the intracellular content of T3. The inhibitory effect of propranolol 200 μM was not antagonized by equimolar concentrations of adrenaline.

Our study suggests that the inhibitory effect of propranolol on the conversion of T4 to T3 in hepatocytes is caused by a direct chemical effect of the drug unrelated to its β-blocking and membrane stabilizing properties.

Key-Words

Rat Hepatocytes - Thyroxine - Triiodothyronine - β-Blocking Drugs - Propranolol - Timolol - Oxprenolol - Atenolol - Metoprolol - Adrenaline

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