Final answer:
A person taking exogenous thyroid hormone would have decreased endogenous thyroxine secretion and increased TRH secretion while taking this pill.
Step-by-step explanation:
A person taking exogenous thyroid hormone would have decreased endogenous thyroxine secretion and increased TRH secretion while taking this pill.
The secretion of thyroid hormones, including thyroxine (T4), is regulated by a negative feedback loop involving thyrotropin-releasing hormone (TRH) from the hypothalamus and thyroid-stimulating hormone (TSH) from the pituitary gland. Exogenous thyroid hormone, when taken as a pill, can inhibit the production and secretion of endogenous T4, leading to a decrease in its secretion. In response to the lower levels of T4, TRH secretion is increased to stimulate the release of TSH, which in turn stimulates the secretion of exogenous thyroid hormone.