别 称 | 1,3,5-Estratriene-3,17β-diol, 17β-Estradiol, 3,17β-Dihydroxy-1,3,5(10)-estratriene;Dihydrofolliculin; β-Estradiol |
生物活性/药理作用 | Therapeutic Estradiol is a steroid sex hormone vital to the maintenance of fertility and secondary sexual characteristics in females. Typically esterified, estradiol derivatives are formulated for oral or parenteral administration. As the primary, most potent estrogen hormone produced by the ovaries, estradiol binds to and activates specific nuclear receptors. Estradiol exhibits mild anabolic and metabolic properties, and increases blood coagulability. Exogenous estrogens are metabolized in the same manner as endogenous estrogens. Circulating estrogens exist in a dynamic equilibrium of metabolic interconversions. These transformations take place mainly in the liver. Estradiol is converted reversibly to estrone, and both can be converted to estriol, which is the major urinary metabolite. Estrogens also undergo enterohepatic recirculation via sulfate and glucuronide conjugation in the liver, biliary secretion of conjugates into the intestine, and hydrolysis in the gut followed by reabsorption. In postmenopausal women, a significant proportion of the circulating estrogens exist as sulfate conjugates, especially estrone sulfate, which serves as a circulating reservoir for the formation of more active estrogens. Estrogen mediates its effects across the body through potent agonism of the Estrogen Receptor (ER), which is located in various tissues including in the breasts, uterus, ovaries, skin, prostate, bone, fat, and brain. Estradiol binds to both subtypes of the Estrogen Receptor: Estrogen Receptor Alpha (ERα) and Estrogen Receptor Beta (ERβ). Estradiol also acts as a potent agonist of G Protein-coupled Estrogen Receptor (GPER), which has recently been recognized as a major mediator of estradiol's rapid cellular effects [A31620]. When the estrogen receptor has bound its ligand it can enter the nucleus of the target cell, and regulate gene tranion which leads to formation of messenger RNA. The mRNA interacts with ribosomes to produce specific proteins that express the effect of estradiol upon the target cell. 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. |
