<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Baker, M. E.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">What are the physiological estrogens?</style></title><secondary-title><style face="normal" font="default" size="100%">Steroids</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Steroids</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Androstenediol/chemistry/metabolism/pharmacology</style></keyword><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Bone and Bones/drug effects/physiology</style></keyword><keyword><style  face="normal" font="default" size="100%">Brain/drug effects/physiology</style></keyword><keyword><style  face="normal" font="default" size="100%">Estradiol/chemistry/metabolism/pharmacology</style></keyword><keyword><style  face="normal" font="default" size="100%">Estriol/chemistry/metabolism/pharmacology</style></keyword><keyword><style  face="normal" font="default" size="100%">Estrogen Receptor alpha/*genetics/met</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year><pub-dates><date><style  face="normal" font="default" size="100%">Mar</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/23313336</style></url></web-urls></urls><number><style face="normal" font="default" size="100%">3</style></number><edition><style face="normal" font="default" size="100%">2013/01/15</style></edition><volume><style face="normal" font="default" size="100%">78</style></volume><pages><style face="normal" font="default" size="100%">337-40</style></pages><isbn><style face="normal" font="default" size="100%">1878-5867 (Electronic)00</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Estradiol (E2) is the principal physiological estrogen in mammals. E2 and its active metabolites, estrone and estriol have a characteristic phenolic A ring, unlike progesterone, testosterone, cortisol and aldosterone, which have an A ring containing a C3-ketone, a Delta(4) bond and a C19 methyl group. Crystal structures of E2 in the estrogen receptor (ER) confirm the importance of the A ring in stabilizing E2 in the ER. However, other steroids, including Delta(5)-androstenediol, 5alpha-androstanediol and 27-hydroxycholesterol, which have a saturated A ring containing a 3beta-hydroxyl and a C19 methyl group, also mediate physiological responses through binding to estrogen receptor-alpha (ERalpha) and ERbeta. Moreover, selective estrogen response modulators (SERMs) with diverse structures also regulate transcription of ERalpha and ERbeta. Our understanding of the physiological responses mediated by these &quot;alternative&quot; estrogens is in its infancy. Further studies of the role of these steroids and SERMs in regulating responses mediated by ERalpha and ERbeta a variety of tissues, during different stages of development, are likely to uncover additional estrogenic activities.&lt;/p&gt;
</style></abstract><accession-num><style face="normal" font="default" size="100%">23313336</style></accession-num><notes><style face="normal" font="default" size="100%">&lt;p&gt;Steroids. 2013 Mar;78(3):337-40. doi: 10.1016/j.steroids.2012.12.011. Epub 2013 Jan 9.&lt;/p&gt;
</style></notes><auth-address><style face="normal" font="default" size="100%">Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0693, USA. mbaker@ucsd.edu</style></auth-address></record></records></xml>