Sulfation of thyroid hormone by estrogen sulfotransferase

Sulfation is one of the pathways by which thyroid hormone is inactivated, l odothyronine sulfate concentrations are very high in human fetal blood and amniotic fluid, suggesting important production of these conjugates in uter o. Human estrogen sulfotransferase (SULT1E1) is expressed among other tissu es in the uterus. Here we demonstrate for the first time that SULT1E1 catal yzes 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 f or rT(3) approximate to 3,3'-T2 > T-3 approximate to T-4 Thus, a single enz yme is capable of sulfating two such different hormones as the female sex h ormone and thyroid hormone. The potential role of SULT1E1 in fetal thyroid hormone metabolism needs to be considered.