Antihormonal substance used to induce ovulation:
**Core Concept**
Clomiphene citrate is a selective estrogen receptor modulator (SERM) that acts as an antihormonal substance to induce ovulation in anovulatory women. It primarily works by binding to estrogen receptors in the hypothalamus, which leads to a decrease in negative feedback to the hypothalamus, resulting in an increase in gonadotropin-releasing hormone (GnRH) secretion and subsequently, a surge in luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels.
**Why the Correct Answer is Right**
Clomiphene citrate's mechanism of action involves binding to estrogen receptors in the hypothalamus, which decreases the negative feedback to the hypothalamus, leading to an increase in GnRH secretion. This results in a surge in LH and FSH levels, stimulating the development of ovarian follicles and ovulation. Clomiphene citrate's action is specific to the hypothalamic-pituitary-gonadal axis, making it a useful agent for inducing ovulation in anovulatory women.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incomplete and cannot be evaluated as a correct or incorrect answer.
**Option B:** There is not enough information to accurately evaluate this option as a correct or incorrect answer.
**Option C:** This option is not relevant to the antihormonal substance used to induce ovulation.
**Option D:** This option is not relevant to the antihormonal substance used to induce ovulation.
**Clinical Pearl / High-Yield Fact**
Clomiphene citrate is a first-line treatment for inducing ovulation in anovulatory women due to its efficacy and relatively low risk of side effects.
**Correct Answer:** C. Clomiphene citrate.