Which of the following statements applies to lipophilic hormones?
A)They include catecholamines.
B)They bind with receptors located inside their target cells.
C) They activate second-messenger systems within their target cells.
D) They circulate as free hormones.

Question

Quizplus · Accepted Answer

Lipophilic hormones, including steroid hormones and thyroid hormones, bind with receptors located inside their target cells, since they are able to cross the cell membrane due to their lipid solubility. This is in contrast to hydrophilic hormones, such as peptide hormones and catecholamines, which bind with receptors located on the surface of their target cells and activate second-messenger systems. Lipophilic hormones also typically circulate bound to carrier proteins rather than as free hormones in the bloodstream. Therefore, option B is the correct choice. Option A is incorrect because catecholamines are hydrophilic hormones. Option C applies to hydrophilic hormones, and option D is not generally true for lipophilic hormones.

Which of the Following Statements Applies to Lipophilic Hormones