Which statement concerning thyroxin is correct?
A) It is formed by coupling one MIT and one DIT within the colloid.
B) It is produced by the C cells of the thyroid gland.
C) It exerts a calorigenic effect.
D) It inhibits thyroid-stimulating immunoglobulin in negative-feedback fashion.

Question

Quizplus · Accepted Answer

Thyroxin (T4) exerts a calorigenic effect, increasing the rate of cellular metabolism throughout the body. Choice A is incorrect because T4 is formed by coupling two DIT molecules within the colloid. Choice B is incorrect because T4 is produced by the follicular cells of the thyroid gland, not the C cells. Choice D is incorrect because thyroid-stimulating immunoglobulin is not inhibited by T4; instead, T4 regulates the secretion of thyroid-stimulating hormone (TSH) in a negative-feedback fashion.

Which Statement Concerning Thyroxin Is Correct