Which estrogen is the most potent and considered the true ovarian hormone?

Which estrogen is the most potent and considered the true ovarian hormone?

• A. Estriol (E3)
• B. Estrone (E1)
• C. 17β-Estradiol (E2)
• D. 16α-Hydroxyestrone

Answer: (C)

The most potent estrogen is 17β-estradiol, and it’s the true ovarian hormone because it is the primary estrogen produced by the ovarian follicles during the reproductive years. It binds estrogen receptors with the highest affinity and drives the main estrogenic actions in target tissues such as the endometrium, breast, and bone. This strong activity underlies its central role in regulating the menstrual cycle, supporting follicle growth, and providing the dominant negative feedback to the hypothalamic-pituitary axis that modulates FSH and LH. Estrone is a weaker estrogen and becomes more prominent after menopause, largely produced by peripheral conversion of androgens in adipose tissue. Estriol is typically associated with pregnancy and tends to be less potent in nonpregnant tissues. 16α-hydroxyestrone is a metabolite with estrogenic activity but is not the principal ovarian estrogen.

The most potent estrogen is 17β-estradiol, and it’s the true ovarian hormone because it is the primary estrogen produced by the ovarian follicles during the reproductive years. It binds estrogen receptors with the highest affinity and drives the main estrogenic actions in target tissues such as the endometrium, breast, and bone. This strong activity underlies its central role in regulating the menstrual cycle, supporting follicle growth, and providing the dominant negative feedback to the hypothalamic-pituitary axis that modulates FSH and LH.

Estrone is a weaker estrogen and becomes more prominent after menopause, largely produced by peripheral conversion of androgens in adipose tissue. Estriol is typically associated with pregnancy and tends to be less potent in nonpregnant tissues. 16α-hydroxyestrone is a metabolite with estrogenic activity but is not the principal ovarian estrogen.