A 28-year-old woman with PCOS and hirsutism is prescribed spironolactone. Beyond its diuretic action, spironolactone helps PCOS by:
- A Blocking androgen receptors in peripheral tissues (hair follicles, sebaceous glands) and inhibiting 5-alpha reductase, reducing dihydrotestosterone binding ✓
- B Inhibiting CYP17alpha, reducing androgen synthesis in the adrenal cortex and ovarian theca cells
- C Increasing sex hormone binding globulin (SHBG) synthesis in the liver, reducing free androgen levels
- D Stimulating LH suppression via negative feedback at the anterior pituitary, reducing thecal androgen production
Correct answer: A. Blocking androgen receptors in peripheral tissues (hair follicles, sebaceous glands) and inhibiting 5-alpha reductase, reducing dihydrotestosterone binding
Explanation
Spironolactone has anti-androgenic properties independent of its mineralocorticoid antagonism. It directly blocks androgen receptors (AR) in peripheral tissues such as hair follicles and sebaceous glands, reducing DHT- and testosterone-driven hair growth and acne. It also weakly inhibits 5-alpha reductase (the enzyme converting testosterone to the more potent DHT) and partially inhibits adrenal androgen synthesis. These effects make it a useful off-label agent for hirsutism in PCOS.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.