Oestradiol

Oestradiol, E2, is an oestrogen, a steroidal hormone secreted by the ovaries. It is a main female hormone. Oestradiol regulates female characteristics, the maturation of female sex organs and the oestrus and menstrual cycle. It stimulates the production of mammary glands.
The serum concentrations of oestradiol and other female hormones change during the menstrual cycle. During gestation there is a high serum concentrations of oestradiol, E3. During menopause, oestrone has the higher concentration.
Oestradiol and oestrone can interchange. Oestradiol has a big effect on bone formation. Women past menopause have an accelerated loss of bone because they have less oestrogen.
Oestradiol also has some functions in males. Its serum concentration in men is &lt; 35 pg/mL, level equivalent to that seen in post-menopausal women.