title: Type 3 iodothyronine deiodinase is highly expressed in the human uteroplacental unit and in fetal epithelium.
abstract: Type 3 iodothyronine deiodinase (D3) is the major physiologic inactivator of thyroid hormone. This selenoenzyme, previously identified in human placenta and brain, catalyzes the inner-ring deiodination of T(4) to reverse T(3) and T(3) to 3, 3'-diiodothyronine, both of which are biologically inactive. We analyzed D3 expression in several human adult and fetal tissues by immunohistochemistry and correlated the results with D3 activity assays where possible. High D3 expression was present in the placental syncytiotrophoblasts and cytotrophoblasts, endothelium of fetal vessels, and maternal decidua. D3 was also present at other sites of maternal-fetal interface, including the umbilical arteries and vein and the fetal respiratory, digestive, and urinary tract epithelium. Surprisingly, D3 was also present in the endometrial glands of nonpregnant human uteri, and endometrial activity approximated that of term placenta. The presence of D3 at maternal-fetal interfaces is consistent with its role in modulating the thyroid status of the human fetus and its expression in endometrium suggests that local regulation of thyroid status is important in implantation.
authors.affiliation: Division of Endocrinology, Diabetes, and Hypertension, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA. stephen.huang@tch.harvard.edu
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Huang
authors.forename: David M
authors.initials: DM
authors.lastname: Dorfman
authors.forename: David R
authors.initials: DR
authors.lastname: Genest
authors.forename: Domenico
authors.initials: D
authors.lastname: Salvatore
authors.forename: P Reed
authors.initials: PR
authors.lastname: Larsen
mesh_terms: D004717:Endometrium / Q000737:chemistry; D005260:Female; D005333:Fetus / Q000201:enzymology*; D006801:Humans; D007150:Immunohistochemistry; D007453:Iodide Peroxidase / Q000032:analysis*; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D013974:Thyroxine / Q000378:metabolism; D014284:Triiodothyronine / Q000378:metabolism; D014470:Umbilical Cord / Q000201:enzymology; D014599:Uterus / Q000201:enzymology*
chemical_list: D014284:Triiodothyronine; C117274:iodothyronine deiodinase type III; D007453:Iodide Peroxidase; D013974:Thyroxine