Drugs that suppress growth hormone release in acromegaly include the following except:

Correct Answer: D

Rationale: The correct answer is D: Nafarelin. Nafarelin is a gonadotropin-releasing hormone agonist used for conditions like endometriosis and precocious puberty, not for acromegaly. A: Bromocriptine and B: Somatostatin analogs (e.g., C: Octreotide) are used to suppress growth hormone release in acromegaly by targeting the pituitary gland.

Correct Answer: D

Rationale: The correct answer is D because adrenocorticotropic hormone (ACTH) is primarily used for diagnosing pituitary-adrenal axis disorders. ACTH stimulates the adrenal glands to produce cortisol, so measuring cortisol levels after administering ACTH helps identify disorders like Cushing's syndrome or adrenal insufficiency. Choices A, B, and C are incorrect because ACTH is not used to treat Addison's disease, congenital adrenal hyperplasia, or autoimmune diseases. Instead, these conditions may require cortisol replacement therapy, specific enzyme inhibitors, or immunosuppressants, respectively.

Correct Answer: A

Rationale: The correct answer is A. Auricular fibrillation is not a complication of overtreatment with thyroxine. Thyroxine is a thyroid hormone that can increase heart rate and cardiac output, potentially leading to complications such as angina pectoris, congestive heart failure, and acceleration of atherosclerosis. However, auricular fibrillation, also known as atrial fibrillation, is not directly caused by thyroxine over-treatment. It is important to differentiate between the potential complications of thyroxine therapy to ensure proper management and avoid unnecessary risks to the patient's health.

Correct Answer: A

Rationale: Propyl thiouracil inhibits the enzyme 5'-deiodinase, which is responsible for converting thyroxine (T4) to triiodothyronine (T3) peripherally. Methimazole and carbimazole primarily inhibit thyroid hormone synthesis. Radioactive iodine destroys thyroid tissue. Therefore, choice A is correct as it specifically targets the peripheral conversion of T4 to T3.

Correct Answer: D

Rationale: The correct answer is D: 60 days. This is because the physical half-life of a radioactive substance refers to the time it takes for half of the radioactive atoms to decay. In the case of 131I, it has a physical half-life of 8 days. However, 131I undergoes beta decay to form stable xenon-131, which has a longer half-life. Therefore, the effective half-life of 131I is longer, approximately 60 days. Summary: A: 8 hours - Incorrect, too short for the physical half-life of 131I. B: 8 days - Partially correct, but the effective half-life is longer. C: 16 days - Incorrect, not the effective half-life of 131I. D: 60 days - Correct, reflects the effective half-life of 131I due to its decay process.