Reduction of plasma triiodothyronine (T3) induced by propranolol.
The effect of propranolol on plasma triiodothyronine (T3), thyroxine (T4) and triiodothyronine uptake by Sephadex G-25 (RT3U%) was studied in fourteen thyrotoxic patients and eight normal volunteers. 40 mg of propranolol as a single oral dose caused significant reduction in total serum T3 which began 60 min after administration. No significant changes were observed in T4 and RT3U% values. Plasma T3 levels remained suppressed during a 5 day course of treatment with propranolol. These results suggest that propranolol has a direct effect on peripheral metabolism of T3 rather than on thyroid hormone secretion.
D000328:Adult; D005260:Female; D006111:Graves Disease / Q000097:blood; D006801:Humans; D008297:Male; D011433:Propranolol / Q000008:administration & dosage / Q000494:pharmacology*; D013974:Thyroxine / Q000097:blood; D013997:Time Factors; D014284:Triiodothyronine / Q000097:blood*
D014284:Triiodothyronine; D011433:Propranolol; D013974:Thyroxine