A distinctive feature of the mechanism of action of thyroid hormones and steroid hormones is that
A)these hormones are regulated by feedback loops.
B)target cells react more rapidly to these hormones than to local regulators.
C)these hormones bind with specific receptor proteins on the plasma membrane of target cells.
D)these hormones bind to receptors inside cells.
E)these hormones affect metabolism.

Question

Quizplus · Accepted Answer

Thyroid hormones and steroid hormones bind to receptors inside cells, in the cytoplasm or nucleus, and impact gene expression. This is different from local regulators, such as neurotransmitters or paracrine signals, which bind to receptors on the plasma membrane. The mechanism of action of these hormones is also regulated by feedback loops and affects metabolism, but these characteristics are not unique to thyroid hormones and steroid hormones, so they do not make the best choice.

A Distinctive Feature of the Mechanism of Action of Thyroid