These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Modulation of pituitary responsiveness to thyrotropin-releasing hormone by triiodothyronine.
    Author: Shenkman L, Mitsuma T, Hollander CS.
    Journal: J Clin Invest; 1973 Jan; 52(1):205-9. PubMed ID: 4629908.
    Abstract:
    The relative roles of triiodothyronine (T(3)) and thyroxine (T(4)) in modulating pituitary responsiveness to thyrotropin-releasing hormone (TRH) have been assessed. (a) 10 hyperthyroid patients with elevated serum T(2) and T(4) levels showed no pituitary response to TRH. After 2 wk of propylthiouracil therapy T(4) levels had fallen to normal in only five patients while T(2) levels were normal in all. Pituitary responsiveness to TRH returned in all patients with normal or high T(4) concentrations. (b) Patients with isolated elevations of serum T(3) (T(3) toxicosis) failed to respond to TRH. TRH responsiveness was restored when T(3) levels fell to normal after propylthiouracil therapy. (c) When pituitary responsiveness to TRH was tested 60 min after a single oral dose of 50 mug of T(3), which increased serum T(3) levels to slightly above the normal range, no rise in thyrotropin (TSH) was seen in six subjects. These findings indicate that T(3) elevations alone can rapidly inhibit pituitary responsiveness to TRH.
    [Abstract] [Full Text] [Related] [New Search]