The 3-methyl ether of ethinyl estradiol. It must be demethylated to be biologically active. It is used as the estrogen component of many combination ORAL contraceptives. [PubChem] (en)
Mestranol is the 3-methyl ether of ethinylestradiol. Ethinylestradiol, is a synthetic derivative of estradiol. Ethinylestradiol is orally bio-active and the estrogen used in almost all modern formulations of combined oral contraceptive pills. It binds to (and activates) the estrogen receptor. Mestranol is a biologically inactive prodrug of ethinylestradiol to which it is demethylated in the liver with a conversion efficiency of 70%. Estrogens diffuse into their target cells and interact with a protein receptor. Target cells include the female reproductive tract, the mammary gland, the hypothalamus, and the pituitary. Estrogens increase the hepatic synthesis of sex hormone binding globulin (SHBG), thyroid-binding globulin (TBG), and other serum proteins and suppress follicle-stimulating hormone (FSH) from the anterior pituitary. The combination of an estrogen with a progestin suppresses the hypothalamic-pituitary system, decreasing the secretion of gonadotropin-releasing hormone (GnRH). (en)