What is the role of LH in the menstrual cycle?

• A. LH triggers ovulation and stimulates the corpus luteum to produce progesterone.
• B. LH directly builds the endometrial lining.
• C. LH inhibits ovulation.
• D. LH reduces testosterone production.

Answer: (A)

LH surge triggers ovulation and stimulates the corpus luteum to produce progesterone. As the dominant follicle matures, a rise in LH causes the follicle to rupture and release the oocyte (ovulation). The remaining follicular tissue then luteinizes to form the corpus luteum, which secretes progesterone (and some estrogen) to transform the endometrium into a secretory state, making it receptive to potential implantation. If fertilization doesn’t occur, the corpus luteum regresses and progesterone falls, leading to menstruation. LH isn’t responsible for building the endometrium—that’s driven by estrogen and progesterone—and it does not inhibit ovulation. In the female cycle, LH also stimulates theca cells to produce androgens (precursors to estrogen), not reduce testosterone.