Question

Which of the following is glucocorticoid synthesis inhibitor?

• A. Mifepristone
• B. Flutamide
• C. Finasteride
• D. Metyrapone

Answer 1

The Correct Option is D

Step 1: Cortisol is built in the adrenal cortex through a chain of CYP enzymes; the final step adding the 11-hydroxyl group uses $11\beta$-hydroxylase.

Step 2: Knock out that last hydroxylation and cortisol output falls. Metyrapone does exactly this by inhibiting $11\beta$-hydroxylase, leaving 11-deoxycortisol to accumulate.

Step 3: The remaining options act at receptors or other pathways: mifepristone blocks the glucocorticoid receptor, flutamide blocks the androgen receptor, and finasteride blocks dihydrotestosterone formation.

Step 4: Only metyrapone interrupts actual cortisol synthesis.

\[\boxed{\text{Metyrapone}}\]