Title: Evidence for Extrathyroidal Formation of 3-Iodothyronamine in Humans as Provided by a Novel Monoclonal Antibody-Based Chemiluminescent Serum Immunoassay
Abstract: Thyronamines are thyronergic metabolites of thyroid hormones. Lack of reliable and sensitive detection methods for endogenous 3-iodothyronamine (3-T(1)AM) has so far hampered progress in understanding their physiological action and role in endocrine homeostasis or pathophysiology of diseases.We characterized newly generated mouse monoclonal 3-T(1)AM antibodies and established a monoclonal antibody-based chemiluminescence immunoassay as a powerful tool for monitoring 3-T(1)AM levels in investigations addressing altered serum profiles and potential sites of origin and action of 3-T(1)AM in humans.Our exploratory study on 3-T(1)AM serum levels in humans measured 3-T(1)AM concentrations in comparison with thyroid hormones.Thirteen adult healthy subjects, 10 patients with pituitary insufficiency, and 105 thyroid cancer patients participated.INTERVENTIONS included l-T(4) withdrawal in patients with pituitary insufficiency as well as TSH-suppressive T(4) substitution in thyroid cancer patients.3-T(1)AM was reliably quantified in human serum and stable after storage at room temperature and 4 C overnight as well as after four freeze-thaw cycles. The median serum concentration in healthy subjects was 66 ± 26 nm. 3-T(1)AM was also detected in T(4)-substituted thyroid cancer patients. Although free T(4) and T(3) significantly decreased during T(4) withdrawal, 3-T(1)AM levels remained constant for 6 d.Because higher 3-T(1)AM levels are detectable in T(4)-substituted thyroid cancer patients after thyroidectomy/radioiodine treatment compared with healthy controls, we concluded that 3-T(1)AM is mainly produced by extrathyroidal tissues. The serum profile during T(4) withdrawal suggests either a long half-life or persisting 3-T(1)AM release into serum from intracellular thyroid hormone precursors or stores.
Publication Year: 2011
Publication Date: 2011-06-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
Access and Citation
Cited By Count: 76
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot