Acute beta-blockade changes the extracellular distribution of thyroid hormones

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The acute (within hours) changes in the concentrations of T4, T3, reverse-T3 (rT3) and T3 resin uptake test (T3RU) were studied in 31 hyperthyroid patients for 4 h after po treatment with either acebutolol, Oxprenolol, pindolol or timolol. In 21 of the patients, the changes were compared to changes in the serum concentrations of α2-macroglobulin (a macromoleculë) and two middle-sized molecules; thyroid hormone-binding globulin (TBG) and albumin in order to calculate the changes in extracellular distribution of the thyroid hormones and to distinguish between changes due to a changed metabolism and changes due to a changed distribution of the thyroid hormones. Acebutolol, Oxprenolol and timolol caused a decrease in serum T3 after 1/2 h, and acebutolol and Oxprenolol also a decrease in rT3 after 1/2-1 h, the changes reversed within 2 h. A concomitant decrease in serum albumin and TBG suggests a change in the extracellular distribution of middlesized molecules to which thyroid hormones are attached, as an explanation of the acute decrease (1 h) of the thyroid hormones. The small and insignificant change in α2-macroglobulin indicates that the changes are mainly extravascular, but the difference of α2-macroglobulin changes between the drugs (acebutolol/timolol vs pindolol/oxprenolol) could depend on the intrinsic sympathomimetic activity of the drugs.

Original languageEnglish
JournalJournal of Endocrinological Investigation: Official Journal of the Italian Scociety of Endocrinology
Volume13
Issue number4
Pages (from-to)277-281
Number of pages5
ISSN0391-4097
DOIs
Publication statusPublished - Apr 1990

    Research areas

  • acute changes, albumin, beta-adrenergic blockade, Thyroid, α -macroglobulin

ID: 335355612