12-10-2016, 08:13 AM
A 35-year old woman comes to the emergency department due to a "racing heart" and shortness of breath. She has had insomnia and increased anxiety for the past week. Chest x-ray shows cardiomegaly. An electrocardiogram shows sinus tachycardia at 120 beats per minute. Serum thyroid-stimulating hormone (TSH) is decreased and free thyroxine (T4) is increased. Intravenous propranolol is given to the patient. In addition to its beta-receptor blocking activity, propranolol is likely to benefit this patient by decreasing which of the following?
A. Binding of T3 to its receptors
B. New thyroid hormone synthesis
C. Peripheral conversion of T4 to T3
D. Release of T4 by the thyroid gland
E. Serum levels of TSH receptor antibodies
A. Binding of T3 to its receptors
B. New thyroid hormone synthesis
C. Peripheral conversion of T4 to T3
D. Release of T4 by the thyroid gland
E. Serum levels of TSH receptor antibodies