Which hormone is a classic example of positive feedback in the female reproductive system?

Which hormone is a classic example of positive feedback in the female reproductive system?

• A. Insulin
• B. Estradiol
• C. Parathormone
• D. Catecholamines

Answer: (B)

Rising estradiol from the mature ovarian follicle acts on the hypothalamus and anterior pituitary to enhance GnRH and LH secretion, producing the LH surge that triggers ovulation. This temporary switch from negative to positive feedback by estrogen amplifies the hormone signal at the right time, leading to ovulation and formation of the corpus luteum. After ovulation, progesterone from the corpus luteum provides negative feedback again. The other hormones listed don’t create this estrogen-driven positive feedback loop in the ovarian cycle. So, estradiol is the classic example of positive feedback in this system.

Rising estradiol from the mature ovarian follicle acts on the hypothalamus and anterior pituitary to enhance GnRH and LH secretion, producing the LH surge that triggers ovulation. This temporary switch from negative to positive feedback by estrogen amplifies the hormone signal at the right time, leading to ovulation and formation of the corpus luteum. After ovulation, progesterone from the corpus luteum provides negative feedback again. The other hormones listed don’t create this estrogen-driven positive feedback loop in the ovarian cycle. So, estradiol is the classic example of positive feedback in this system.