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Thyroid-Estrogen Interaction

Meaning

The Thyroid-Estrogen Interaction describes the well-established bidirectional regulatory crosstalk between the thyroid hormone system and the sex steroid system, particularly estrogen. Estrogen significantly influences the liver’s production of Thyroxine-Binding Globulin (TBG), the primary transport protein for thyroid hormones. Consequently, elevated estrogen states, such as during pregnancy or while using estrogen-containing contraceptives, increase TBG, which lowers the fraction of free, biologically active thyroid hormone.