This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pharmacology
Mechanism of action of propylthiouracil: 
Select and explain. 
A. inhibition of organification of iodine, B. inhibition of oxidation, C. inhibition of coupling, D. all of the above
D: all of the above
Answer: D: all of the above 
Explanation: Ans. D. All of the aboveThyroid peroxidase enzyme is responsible for oxidation, organification and coupling of thyroid hormone. Thus, propylthiouracil is the inhibitor of thyroid peroxidase enzyme and modulate all the functions.