Thyroid hormone (a small iodinated amine) enters target cells in a manner similar to ___________.
A) steroid hormones, because both diffuse easily into target cells
B) growth hormone, because the thyroid works synergistically with thyroid hormone
C) insulin, because insulin is a small peptide
D) glucagon, because the structure of glucagon is similar to that of thyroid hormone

Question

Quizplus · Accepted Answer

Thyroid hormone is a small molecule and enters target cells by simple diffusion, similar to steroid hormones. It does not require a receptor or specific transport mechanism, unlike insulin or glucagon. While growth hormone and thyroid hormone do work together in some physiological processes, their mechanisms of action are not similar.

Thyroid Hormone (A Small Iodinated Amine) Enters Target Cells in a Manner