Which is a growth hormone receptor antagonist used in acromegaly?

Which is a growth hormone receptor antagonist used in acromegaly?

• A. Pegvisomant
• B. Octreotide
• C. Bromocriptine
• D. Radiation therapy

Answer: (A)

In acromegaly, the goal is to blunt the action of growth hormone on its target tissues, primarily by lowering IGF-1 levels. Pegvisomant fits this approach because it is a pegylated growth hormone receptor antagonist that binds to GH receptors and prevents GH signaling. By blocking the receptor, it stops GH from stimulating IGF-1 production in the liver, reducing the downstream effects and symptoms of acromegaly. This is different from somatostatin analogs like octreotide, which decrease GH secretion from the pituitary rather than blocking the receptor itself. Bromocriptine is a dopamine agonist with variable effects on GH, not a receptor blocker. Radiation therapy reduces pituitary tumor activity or size over time, but it does not directly antagonize the GH receptor. So, the best choice is the agent that directly blocks GH action at its receptor, lowering IGF-1.

In acromegaly, the goal is to blunt the action of growth hormone on its target tissues, primarily by lowering IGF-1 levels. Pegvisomant fits this approach because it is a pegylated growth hormone receptor antagonist that binds to GH receptors and prevents GH signaling. By blocking the receptor, it stops GH from stimulating IGF-1 production in the liver, reducing the downstream effects and symptoms of acromegaly.

This is different from somatostatin analogs like octreotide, which decrease GH secretion from the pituitary rather than blocking the receptor itself. Bromocriptine is a dopamine agonist with variable effects on GH, not a receptor blocker. Radiation therapy reduces pituitary tumor activity or size over time, but it does not directly antagonize the GH receptor.

So, the best choice is the agent that directly blocks GH action at its receptor, lowering IGF-1.