Abstract：
Estrogens regulate important processes in reproductive, skeletal, cardiovascular, and central nervous systems that impact women\'s overall health. Understanding endogenous and exogenously administered estrogen metabolism is vital to determining therapeutic estrogen levels. The present review provides an overview of estrogen metabolites formed in non-pregnant and pregnant women, and those resulting from exogenous estrogen administration. There are four principal endogenous estrogens: estrone (E1), estradiol (E2), estriol (E3), and estetrol (E4). E4, which is produced only in pregnancy, has emerged recently as an estrogen with significant therapeutic potential. E1, E2, and E3 undergo extensive metabolism primarily through phase I (hydroxylation, oxidation, reduction) and phase II (primarily conjugation) reactions, whereas E4 undergoes only phase II reactions. Exogenous estrogens commonly used for menopausal treatment and/or contraception, including micronized E2, conjugated equine estrogens, and ethinyl estradiol, also undergo phase I and phase II reactions, but differ widely in the types of metabolites formed. The mechanisms by which estrogen metabolites are formed and their excretion in urine, bile, and feces, are still poorly understood. We highlight areas that require further research to foster a better understanding of how estrogen metabolism impacts dosing of oral estrogens for therapeutic use, as well as the physiological regulation of endogenous estrogens.
摘要：
雌激素调节生殖中的重要过程，骨骼，心血管,以及影响女性整体健康的中枢神经系统。了解内源性和外源性雌激素代谢对于确定治疗性雌激素水平至关重要。本综述概述了在非妊娠和妊娠妇女中形成的雌激素代谢物，以及外源性雌激素给药产生的那些。有四种主要的内源性雌激素：雌酮（E1），雌二醇（E2），雌三醇(E3),和雌四醇（E4）。E4，仅在怀孕期间产生，最近出现了一种具有显著治疗潜力的雌激素。E1，E2和E3主要通过I期进行广泛的代谢（羟基化，氧化，还原)和II期(主要是缀合)反应，而E4只经历II期反应。通常用于更年期治疗和/或避孕的外源性雌激素，包括微粉化E2，共轭马雌激素，和乙炔雌二醇,还经历I期和II期反应，但是形成的代谢物类型差异很大。雌激素代谢产物的形成机制及其在尿液中的排泄，胆汁,和粪便,仍然知之甚少。我们强调了需要进一步研究的领域，以促进更好地了解雌激素代谢如何影响治疗用途的雌激素剂量。以及内源性雌激素的生理调节。
