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
[{'content': 'Mechanism of action of propylthiouracil: \nSelect and explain. \nA. inhibition of organification of iodine, B. inhibition of oxidation, C. inhibition of coupling, D. all of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: 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.', 'role': 'assistant'}]