Edgar Allen (1892–1943), Edward Doisy (1893–1986)
Removal of the ovaries has long been associated with atrophy of the uterus and the loss of sexual function. Transplanting pieces of ovaries prevents these wasting effects in adult animals and stimulates the development of the uterus in immature animals. During the early decades of the twentieth century, interest centered on the secretions from such ductless or endocrine glands as the ovaries. In 1923, biologist Edgar Allen and biochemist Edward Doisy, working at St. Louis University School of Medicine, found active principles released into the urine from the ovaries of pregnant and nonpregnant women.
In 1929, Doisy isolated one such chemical—the first purified female hormone from the class of compounds collectively called estrogens—which he named theelin, later renamed estrone. In 1935, estradiol, the most active estrogen, was isolated from the ovaries. These were followed by the semisynthetic, orally active ethinyl estradiol (1935), one of the two primary ingredients in Enovid and other oral contraceptives. In 1938, the first laboratory-prepared estrogen, diethylstilbestrol (DES), was introduced, whose use to prevent miscarriages was later associated with an increased risk of cancers of the breast and vagina. The most notable estrogen—and the best-selling drug in the United States in the 1990s—was Premarin (1941), a mixture of estrone and other natural estrogens obtained from pregnant mare urine (hence its trade name). For more than seventy years, Premarin has been used to treat the symptoms of menopause.
Our first thoughts of estrogen typically concern its role as the female sex hormone required for the development of reproductive organs, such as the vagina and uterus, its role in the development and support of the secondary sex characteristics, including the breasts and distribution of body fat, and its critical contribution to the menstrual cycle. Estrogen also has a number of nonsexual physiological effects, such as increasing bone formation, elevating HDL (good) cholesterol, and lowering LDL (bad) cholesterol. Estrogen derivatives are used to treat prostate cancer, and antiestrogen drugs, such as tamoxifen, are employed for breast cancer.
SEE ALSO Diethylstilbestrol (1938), Premarin (1941), Enovid (1960), Tamoxifen (1973).
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Estrogen is one of two female sex hormones that play an important role in preparing a woman’s body for pregnancy. Under its influence, the walls of the uterus increase in size and, on approximately day fifteen of the menstrual cycle, ovulation occurs in anticipation of the ovum (egg) being fertilized by a sperm cell.