Physician Assistant Clinical Knowledge Rating and Assessment Tool (PACKRAT) 3 Practice Exam

Blocking estrogen feedback at the hypothalamus to boost FSH is the key idea. Clomiphene citrate is a selective estrogen receptor modulator that acts as an antagonist at hypothalamic estrogen receptors. By blocking these receptors, it reduces the negative feedback of estrogen, which increases GnRH pulse frequency from the hypothalamus. This drives the pituitary to release more FSH (and some LH), stimulating follicle development and ovulation.

Other options don’t achieve this mechanism. A GnRH agonist like leuprolide initially increases GnRH but then desensitizes the pituitary and suppresses gonadotropin production, not raising FSH via estrogen feedback blockade. Medroxyprogesterone acetate provides progestin to suppress the axis rather than stimulate it. Metformin helps with insulin resistance and can aid ovulation in PCOS, but not by blocking estrogen feedback to increase FSH.