This is because low thyroid hormone levels tell the hypothalamus to release more thyrotropin releasing hormone, or TRH, and tell the pituitary to release more thyroid stimulating hormone, or TSH.

这是由于低甲状腺激素水平刺激下丘脑释放更多促甲状腺激素释放激素，即TRH，并刺激垂体释放更多促甲状腺激素，即TSH。