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Horm Metab Res 1979; 11(1): 39-43
DOI: 10.1055/s-0028-1092680
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© Georg Thieme Verlag KG Stuttgart · New York

Effects of Propylthiouracil and Methylmercaptoimidazol on Metabolism of Thyroid Hormones by Cultured Monkey Hepatocarcinoma Cells

K.  Sorimachi , J.  Robbins
  • Clinical Endocrinology Branch National Institute of Arthritis. Metabolism and Divestive Diseases, National Institutes of Health, Bethesda, Maryland, U.S.A.
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Publication Date:
17 December 2008 (online)

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Abstract

Monkey hepatocarcinoma cell monolayer cultures (NCLP-6E) metabolized thyroxine, 3,5,3'-triiodothyronine, 3,3',5'-triiodothyronine and 3,3'-diiodothyronine by phenolic and nonphenolic ring deiodinations and sulfation of the deiodinated products, as shown in previous work with this system. The effects of the antithyroid drugs, propylthiouracil (PTU) and methylmercaptoimidazole (MMI), on these processes was investigated. PTU, at 0.1 and 1 mM, inhibited only phenolic ring deiodination. MMI at 1 mM had no effect, but 32 mM inhibited deiodination of both rings as well as sulfation. The findings suggest that the increased serum rT3 level caused by PTU in vivo is the result of decreased rT3 deiodination, in contrast to the increased rT3 production which is caused by starvation.

Key words

Propylthiouracil - Methylmercaptoimidazol - Thyroid Hormone Metabolism - Cultured Monkey - Hepatocarcinoma Cells