title: The classic pathways of thyroid hormone metabolism.
abstract: Thyroid hormones (TH) are crucial for growth and development and play an important role in energy homeostasis. Although serum TH levels are relatively constant in the physiological state, TH bioavailability at the tissue and cellular level is dependent on local TH metabolism. Circulating TH produced by the thyroid can be metabolized by a number of different pathways resulting in 1) activation of TH 2) deactivation of TH or 3) excretion of TH and subsequent metabolites. These pathways play an essential role in determining local TH levels and action. The major classical pathways of TH metabolism are deiodination, sulfation, glucuronidation, and ether-link cleavage. This review provides an overview of these pathways, their relative contributions to TH levels in the serum and in various organs and the changes in these pathways elicited by fasting and illness.
authors.affiliation: Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Anne H
authors.initials: AH
authors.lastname: van der Spek
authors.affiliation: Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Eric
authors.initials: E
authors.lastname: Fliers
authors.affiliation: Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. Electronic address: a.boelen@amc.uva.nl.
authors.forename: Anita
authors.initials: A
authors.lastname: Boelen
mesh_terms: D000818:Animals; D005215:Fasting / Q000097:blood / Q000378:metabolism; D053263:Gene Regulatory Networks; D006706:Homeostasis; D006801:Humans; D015398:Signal Transduction; D013963:Thyroid Hormones / Q000097:blood / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D013963:Thyroid Hormones
keywords: Deiodination; Glucuronidation; Sulfation; Thyroid hormone; Thyroid hormone degradation; Thyroid hormone metabolism