Identification of thyroid hormone transporters in humans: different molecules are involved in a tissue-specific manner.

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Fujiwara K, Adachi H, Nishio T, Unno M, Tokui T, Okabe M, Onogawa T, Suzuki T, Asano N, Tanemoto M, Seki M, Shiiba K, Suzuki M, Kondo Y, Nunoki K, Shimosegawa T, Iinuma K, Ito S, Matsuno S, Abe T

Identification of thyroid hormone transporters in humans: different molecules are involved in a tissue-specific manner.

Endocrinology. 2001 May;142(5):2005-12.

PubMed ID

11316767 [ View in PubMed

]

Abstract

We have recently identified that rat organic anion transporters, polypeptide2 (oatp2) and oatp3, both of which transport thyroid hormones. However, in humans the molecular organization of the organic anion transporters has diverged, and the responsible molecule for thyroid hormone transport has not been clarified, except for human liver-specific transporter (LST-1) identified by us. In this study we isolated and characterized a novel human organic anion transporter, OATP-E from human brain. The isolated complementary DNA encodes a polypeptide of 722 amino acids with 12 transmembrane domains. A rat counterpart, oatp-E, was also identified. Homology analysis and the phylogenetic tree analysis revealed that OATP-E/oatp-E is a subfamily of the organic anion transporter. Human OATP-E transported 3,3',5-triiodo-L-thyronine (K(m), 0.9 microM), thyronine, and rT(3) in a Na(+)-independent manner. Although the clone was isolated from the brain, OATP-E messenger RNA was abundantly expressed in various peripheral tissues. The rat counterpart, oatp-E, also transported 3,3',5-triiodo-L-thyronine. In addition, in this study we revealed that human OATP, which is exclusively expressed in the brain, transported 3,3',5-triiodo-L-thyronine (K(m), 6.5 microM), T(4) (K(m), 8.0 microM), and rT(3). These data suggest that in humans, several different molecules are involved in transporting thyroid hormone: OATP in the brain, LST-1 in the liver, and OATP-E in peripheral tissues.

DrugBank Data that Cites this Article

Drug Transporters

Drug	Transporter	Kind	Organism	Pharmacological Action	Actions
Dextrothyroxine	Solute carrier organic anion transporter family member 4A1	Protein	Humans	Unknown	Not Available	Details
Liothyronine	Solute carrier organic anion transporter family member 1A2	Protein	Humans	Unknown	Substrate	Details
Liothyronine	Solute carrier organic anion transporter family member 4A1	Protein	Humans	Unknown	Substrate Inhibitor	Details
Liotrix	Solute carrier organic anion transporter family member 1A2	Protein	Humans	Unknown	Substrate	Details
Liotrix	Solute carrier organic anion transporter family member 4A1	Protein	Humans	Unknown	Substrate Inhibitor	Details
Taurocholic acid	Solute carrier organic anion transporter family member 4A1	Protein	Humans	Unknown	Inhibitor	Details

Polypeptides

Name	UniProt ID
Solute carrier organic anion transporter family member 4A1	Q96BD0	Details