Sulfation of thyroid hormone by estrogen sulfotransferase

Sulfation is one of the pathways by which thyroid hormone is inactivated, lodothyronine sulfate concentrations are very high in human fetal blood and amniotic fluid, suggesting important production of these conjugates in utero. Human estrogen sulfotransferase (SULT1E1) is expressed among other tissues in the uterus. Here we demonstrate for the first time that SULT1E1 catalyzes the facile sulfation of the prohormone T-4, the active hormone Tg and the metabolites rT(3) and 3,3'-diiodothyronine (3,3'-T-2) with preference for rT(3) approximate to 3,3'-T2 > T-3 approximate to T-4 Thus, a single enzyme is capable of sulfating two such different hormones as the female sex hormone and thyroid hormone. The potential role of SULT1E1 in fetal thyroid hormone metabolism needs to be considered.