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Pregnant Rat Uterus Expresses High Levels Of The Type 3 Iodothyronine Deiodinase, Valerie Anne Galton, Elena Martinez, Arturo Hernandez, Emily A. St. Germain, Joanne M. Bates, Donald L. St. Germain

Dartmouth Scholarship

Although thyroid hormones are critically important for the coordination of morphogenic processes in the fetus and neonate, premature exposure of the embryo to levels of the hormones present in the adult is detrimental and can result in growth retardation, malformations, and even death. We report here that the pregnant rat uterus expresses extremely high levels of the type 3 iodothyronine deiodinase (D3), which inactivates thyroxine and 3,3′,5-triiodothyronine by 5-deiodination. Both D3 mRNA and activity were present at the implantation site as early as gestational day 9 (E9), when expression was localized using in situ hybridization to uterine mesometrial and antimesometrial …