This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Anatomy
Triiodothyronine (T3) as compared to T4: 
Select and explain. 
A. Is more plasma protein bound, B. Is shoer acting, C. Is less potent, D. Has delayed action
B: Is shoer acting
Answer: B: Is shoer acting 
Explanation: (Ref: KDT 6/e p247) T3 is the main active thyroid hormone. It is more potent (less plasma protein bound) and faster acting than T4. However, sho duration of action limits its use for the treatment of hypothyroidism (requires life long treatment). T3 is indicated for the treatment of myxedema coma.