Polycystic ovarian syndrome (PCOS) pathophysiology involves what primary mechanism?

Polycystic ovarian syndrome (PCOS) pathophysiology involves what primary mechanism?

• A. Primary hypothyroidism causes amenorrhea.
• B. Excess progesterone causes hair loss.
• C. Low estrogen with normal androgen levels.
• D. Insulin resistance with elevated LH driving increased ovarian androgen production.

Answer: (D)

PCOS pathophysiology centers on insulin resistance with resulting hyperinsulinemia that amplifies ovarian androgen production, especially when LH is elevated. Insulin acts on the ovarian theca cells to boost androgen synthesis, and LH further drives this androgen output. At the same time, hyperinsulinemia lowers liver SHBG, increasing circulating free testosterone. The net effect is hyperandrogenism with disrupted follicular development, leading to anovulation and the clinical features of PCOS. Other possibilities don’t fit this pattern: hypothyroidism causes menstrual irregularities through thyroid hormone effects, not the ovarian androgen–driven mechanism of PCOS; progesterone excess isn’t the driver of hair loss in this condition; and estrogen in PCOS is typically normal to elevated rather than low, due to peripheral aromatization and ongoing ovarian activity.

PCOS pathophysiology centers on insulin resistance with resulting hyperinsulinemia that amplifies ovarian androgen production, especially when LH is elevated. Insulin acts on the ovarian theca cells to boost androgen synthesis, and LH further drives this androgen output. At the same time, hyperinsulinemia lowers liver SHBG, increasing circulating free testosterone. The net effect is hyperandrogenism with disrupted follicular development, leading to anovulation and the clinical features of PCOS.

Other possibilities don’t fit this pattern: hypothyroidism causes menstrual irregularities through thyroid hormone effects, not the ovarian androgen–driven mechanism of PCOS; progesterone excess isn’t the driver of hair loss in this condition; and estrogen in PCOS is typically normal to elevated rather than low, due to peripheral aromatization and ongoing ovarian activity.