Thyroid hormone metabolism and the developing human lung

Thyroid hormones are involved in the regulation of fetal lung development, and maturation is accelerated in animal models by antepartum exposure to ra ised concentrations of the receptor-active thyroid hormone triiodothyronine and glucocorticoids, It is essential that the nature of the regulation of the spatial and temporal metabolism of iodothyronines in the human fetus an d infant is known before effective therapies can be developed to modify hum an lung maturation. Thyroid hormone bioavailability to the human fetus is r egulated in part by enzymatic deiodination and reversible sulfation of iodo thyronines, with contributions from other factors such as fetomaternal and fetoamniotic hormone transfers, fetal thyroid gland production, and the act ivities of plasma membrane transporters mediating uptake of iodothyronines from plasma into tissues. Copyright (C) 2001 S. Karger AG, Basel.