Article
Estrogen
Estrogen is a primary female sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics, including breast development. For more on hormonal cycles, see hormonal_cycle. For its role in sexuality, see horniness and desire_and_pleasure.
Functions
- Stimulates breast growth during puberty and pregnancy. Works with growth hormone to promote ductal development and fat accumulation in the breast. See growth_hormone.
- Regulates menstrual cycle
- Increases oxytocin secretion and oxytocin receptor expression, especially in the uterus and brain, enhancing sensitivity to oxytocin during labor, lactation, and social bonding (see oxytocin).
- Influences fat distribution (see hips)
Pubertal Timing Context
Estradiol production rises early in gonadarche in response to pulsatile LH/FSH driven by upstream kisspeptin stimulation; adequate energy reserves signaled by leptin permit this activation. Early sustained estradiol accelerates epiphyseal maturation (see bone_age), while physiologic levels coordinate with growth_hormone for peak height velocity (see pubertal_growth_spurt).