Carrier-Mediated Thyroid Hormone Transport into Placenta by Placental Transthyretin

Our results suggest that human placenta and choriocarcinoma cells secrete transthyretin, which binds extracellular T(4), and that T(4) binding results in increased internalization of TTR-T(4) complex. TTR production by trophoblasts may represent a mechanism to allow transfer of maternal thyroid hormone to the fetal circulation that could have important implications for fetal development.