Estrogen

Estrogen or oestrogen is a group of female hormones.^[1] It includes oestrone (E1), oestradiol (E2), and oestriol (E3).

Oestradiol is the most important oestrogen. Oestrogen is mainly secreted by the ovary, a small amount by the liver, adrenal cortex, and breast. In pregnancy, the placenta can also have a lot of secretion. Male testes also secrete a small amount. Ovary mainly secretes β-estradiol, other estrogens are less important.^[2]

Oestrogen helps women grow during puberty and is part of the menstrual cycle. During menopause, oestrogen levels go down. The male hormone that is similar is androgen.

1. ↑ The word comes from the Greek οἶστρος, meaning gadfly. Its use here is not literal.
2. ↑ Whitehead S.A. & Nussey S. 2001. Endocrinology: an integrated approach. Oxford: BIOS. ISBN 1-85996-252-1