Estrogen << EHS truh juhn >> is any of a group of chemically similar hormones that cause the growth and development of female sexual characteristics in human beings and other animals. Estrogens also influence the female reproductive cycle. Of several forms produced in a woman’s body, estradiol is the strongest.
During a girl’s preteen or early teenage years, her ovaries begin to secrete increasing amounts of estrogens into the bloodstream. Estrogens cause the girl to develop breasts and rounded hips and cause the genital organs to enlarge and mature. Estrogens also stimulate the lining of the uterus to thicken. The hormone progesterone limits this growth. The uterine lining is shed during menstruation each month. The amount of estrogens secreted by the ovaries changes during the menstrual cycle. As the woman grows older, her ovaries secrete smaller amounts of estrogens. After the level of estrogens in the blood becomes too low to stimulate the uterine lining, menstruation no longer occurs. The woman is then said to have reached menopause.
In both women and men, small amounts of estrogens are produced in fat tissue, muscles, and many other parts of the body. In males, the testes (sex organs) also produce estrogens. The function of estrogens in the male is unclear.
The drug industry produces synthetic estrogens for use in birth control pills and for certain medical therapy. Use of large amounts of synthetic estrogens may harm some patients. The use of birth control pills has been associated in some women with blood clots, high blood pressure, and diabetes. Women who take estrogen without progesterone are at increased risk for cancer of the endometrium (inner lining of the uterus). After menopause, many women receive treatment with estrogens to relieve hot flashes and other symptoms associated with menopause. Women considering such treatment should discuss the possible risks with a physician.
