Adrenocorticotropic hormone is primarily used for:

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: 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.

Correct Answer: C

Rationale: The correct answer is C: Facilitation of neoglucogenesis by liver. Insulin's main role is to lower blood glucose levels by promoting glucose uptake into cells (A) and glycogen synthesis in the liver (B), and inhibiting lipolysis in adipose tissue (D). Neoglucogenesis is the process of synthesizing new glucose molecules, which is not a function of insulin. Therefore, choice C is incorrect as insulin does not facilitate neoglucogenesis.

Correct Answer: B

Rationale: The correct answer is B: 8-10 hours. Lente insulin is a type of intermediate-acting insulin that typically lasts around 8-10 hours. This is because it is a mixture of insulin crystals and zinc, which delays its absorption and extends its duration of action. Choice A (2-4 hours) is too short for lente insulin. Choice C (20-24 hours) and D (30-36 hours) are too long for lente insulin, which is considered intermediate-acting. Therefore, the correct answer is B as it aligns with the expected duration of action for lente insulin.