A 29-year-old woman with PCOS is prescribed combined oral contraceptive pills for cycle regulation and hyperandrogenism. Which mechanism best describes how COCPs reduce circulating androgens in PCOS?
- A Suppression of LH-driven ovarian androgen production and increased hepatic SHBG synthesis ✓
- B Direct inhibition of ovarian theca cell steroidogenesis
- C Inhibition of adrenal 17α-hydroxylase activity
- D Blockade of androgen receptors at the hair follicle
Correct answer: A. Suppression of LH-driven ovarian androgen production and increased hepatic SHBG synthesis
Explanation
COCPs reduce androgens by two mechanisms: (1) suppressing pituitary LH, which decreases ovarian theca cell androgen synthesis, and (2) the estrogen component increases hepatic production of sex hormone-binding globulin (SHBG), lowering free testosterone. They do not directly inhibit steroidogenic enzymes or block androgen receptors at the receptor level (though antiandrogens like cyproterone do).
Reference: Yen and Jaffe's Reproductive Endocrinology, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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