When do the highest levels of gonadotropins occur?

When do the highest levels of gonadotropins occur?

• A. During the follicular phase of the menstrual cycle
• B. During the luteal phase of the menstrual cycle
• C. At the midpoint of the menstrual cycle
• D. Several days prior to ovulation

Answer: (C)

Gonadotropins from the pituitary (LH and FSH) rise in a cyclical pattern under ovarian feedback. The highest level occurs around ovulation, when the developing follicle secretes estrogen that switches to strong positive feedback on the pituitary. This drives a dramatic LH surge—the peak of gonadotropin levels—around the middle of the cycle. FSH also increases, but not as much as LH during this surge. After ovulation, progesterone and inhibin from the corpus luteum suppress further gonadotropin release, so levels fall in the luteal phase. So the peak, or highest gonadotropin levels, is at the midpoint of the cycle.

Gonadotropins from the pituitary (LH and FSH) rise in a cyclical pattern under ovarian feedback. The highest level occurs around ovulation, when the developing follicle secretes estrogen that switches to strong positive feedback on the pituitary. This drives a dramatic LH surge—the peak of gonadotropin levels—around the middle of the cycle. FSH also increases, but not as much as LH during this surge. After ovulation, progesterone and inhibin from the corpus luteum suppress further gonadotropin release, so levels fall in the luteal phase. So the peak, or highest gonadotropin levels, is at the midpoint of the cycle.