Cellular entry of thyroid hormones by organic anion transporting polypeptides.
Several transporter families that can transport thyroid hormones have been identified. One of these is represented by the organic anion transporting polypeptide (OATP) gene superfamily, classified within the solute carrier family SLCO. In humans, eleven different OATPs are expressed in various tissues, including the liver, kidney, brain, lung, intestine and placenta. They mediate sodium-independent transport of a variety of amphipathic organic compounds, including thyroid hormones, bile acids, steroid hormones and their conjugates, linear and cyclic peptides, prostaglandins, numerous drugs and other xenobiotics. OATP1C1, which is expressed in the blood-brain barrier and testes, is the thyroid hormone transporter with the highest apparent affinity, with K(m) values of 90.4nM for thyroxine (T(4)) and 127.7nM for reverse T(3) (rT(3)) transport, and could be essential for thyroid hormone delivery to the developing brain. OATP4A1 is expressed in the placenta and could be important for maternal thyroid hormone transport to the developing fetus.
Hagenbuch
Bruno
B
Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, USA. bhagenbuch@kumc.edu
D000818:Animals; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D027361:Organic Anion Transporters / Q000378:metabolism*; D010802:Phylogeny; D013379:Substrate Specificity; D013963:Thyroid Hormones / Q000378:metabolism*; D014018:Tissue Distribution
D027361:Organic Anion Transporters; D013963:Thyroid Hormones