How does estrogen function in the body?
Estrogens, particularly estradiol, are powerful female hormones that make a girl develop into a woman capable of reproduction. Whether from your own ovaries or from an external source, estrogens work in the body by traveling in the blood to body tissues where there are estrogen receptors. Estrogen receptors are found in the brain, breasts, heart, blood vessels, uterus, vagina, bladder, liver, bones, skin, and gastrointestinal tract. Estrogen molecules bind, or attach, to estrogen receptors much like a key fits into a lock, and this leads to effects that vary from one body part to another. Not all parts of the body have estrogen receptors, and not all estrogen receptors are alike. Estrogen receptors in bone tissue are not the same as estrogen receptors in breast tissue, for example. There are other factors that influence the differing effects of estrogen in different parts of the body, but not a great deal is known about these other factors.