Premium
Propranolol has direct antithyroid activity: Inhibition of iodide transport in cultured thyroid follicles
Author(s) -
Murakami Saburo,
Nasu Michiyo,
Fukayama Harushisa,
Krishnan Lalita,
Sugawara Masahiro
Publication year - 1993
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.290110303
Subject(s) - organification , propranolol , iodide , chemistry , endocrinology , medicine , quinidine , iodine , thyroid , atenolol , biology , inorganic chemistry , organic chemistry , blood pressure
The effect of propranolol on the process of thyroid hormone formation was studied in a physiological culture system. Porcine thyroid follicles were preincubated with propranolol for 24 h. Iodide transport, iodine organification, and de novo thyroid hormone formation were measured by incubating these follicles with the mixture of carrier‐free 0·1 μCi Na 125 I and 50 n M NaI for 2 to 6 h at 37°C. A concentration of propranolol greater than 100 μ M inhibited iodide transport in a dose‐dependent manner; this inhibition was non‐competitive with iodide and independent of thyrotropin (TSH). Reduced iodine organification and thyroid hormone formation was seen with 150 μ M propranolol or greater. The inhibitory action of propranolol was not caused by beta‐blocking activity, since D ‐propranolol (devoid of beta‐blocking activity) inhibited iodide transport, and other beta‐blockers (metoprolol, atenolol, and labetalol) did not inhibit iodide transport. The inhibition of iodide transport was most likely caused by membrane stabilizing activity since quinidine, which possess the same membrane stabilizing activity as propranolol, also inhibited iodide transport. TSH‐mediated cAMP generation and Na + K + ATPase activity, membrane functions for iodide transport, were unaffected by propranolol. Our study has shown, for the first time, that propranolol has a direct antithyroid action, namely inhibition of iodide transport in the intact thyroid follicle.