estrogens

Estrogens are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal.

Estrogens are synthesized in all vertebrates as well as some insects. Their presence in both vertebrates and insects suggests that estrogenic sex hormones have an ancient evolutionary history.

Estrogens are used as part of some oral contraceptives, in estrogen replacement therapy for postmenopausal women, and in hormone replacement therapy for trans women.

Three main types of estrogens are estradiol, estrone and estriol. All three are synthesized from androgens by certain enzymes. Estradiol arises from testosterone and estrone from androstenedione.

Like all steroid hormones, estrogens readily diffuse across the cell membrane. Once inside the cell, they bind to and activate estrogen receptors which in turn modulate the expression of many genes. Additionally, estrogens have been shown to activate a G protein-coupled receptor, GPR30.