Which of the following is glucocorticoid receptor blocker?
**Core Concept**
Glucocorticoid receptor blockers are a class of medications that inhibit the action of glucocorticoids, which are steroid hormones that play a crucial role in regulating metabolism, immune response, and inflammation. Glucocorticoids exert their effects by binding to the glucocorticoid receptor (GR), which then translocates to the nucleus to regulate gene expression.
**Why the Correct Answer is Right**
Mifepristone, also known as RU486, is a potent glucocorticoid receptor blocker that has been used primarily for medical abortion. It binds to the GR with high affinity, preventing glucocorticoids from exerting their effects. This blockade of GR activity leads to the inhibition of gene expression that is typically induced by glucocorticoids. Mifepristone's glucocorticoid receptor blocking activity is a key aspect of its therapeutic and abortifacient effects.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not a glucocorticoid receptor blocker. It may be a medication with different pharmacological properties.
**Option B:** This option is incorrect because it does not have glucocorticoid receptor blocking activity.
**Option C:** This option is not a glucocorticoid receptor blocker. It may be a medication with other therapeutic effects.
**Clinical Pearl / High-Yield Fact**
Mifepristone's glucocorticoid receptor blocking activity can lead to adrenal insufficiency, which is a life-threatening condition. This is a critical consideration when prescribing mifepristone for medical abortion or other indications.
**Correct Answer: C. Mifepristone**