Question

How do the pituitary and hypothalamus interact to regulate thyroxine levels?

Answer 1

Thyroid hormone thyroxine (T3, T4, etc) is secreted in response to a trophic hormone released by anterior pituitary. It is named thyrotropin or thyroid stimulating hormone (=TSH).

Anterior pituitary in turn acts under the influence of thyrotropin releasing hormone (=TRH): a neurohormone released by hypothalamus in blood of hypothalamic hypophyseal portal system.