Conversion of T4 to T3 is inhibited by all except:: (A) Propranolol, (B) Propylthiouracil, (C) Amiodarone, (D) Methimazole
Answer is D. Ans. (D) Methimazole(Ref: KDT 8/e p252-253)Methimazole inhibits only thyroid peroxidase whereas propylthiouracil inhibits thyroid peroxidase as well as 5'-deiodinase. Later is involved in peripheral conversion of T4 to T3 (Katzung 12/e p688, Goodman Gilman 12/e p1150)