16α-hydroxy steroid estriol http://purl.bioontology.org/ontology/MEDDRA/10030234 http://purl.bioontology.org/ontology/MESH/D004964 http://purl.bioontology.org/ontology/SNOMEDCT/73723004 http://purl.obolibrary.org/obo/CHEBI_27974 http://purl.obolibrary.org/obo/NCIT_C80154 https://en.wikipedia.org/wiki/Estriol https://en.wikipedia.org/wiki/Estriol_(medication) https://www.wikidata.org/wiki/Q409721 https://www.wikidata.org/wiki/Q55611075 A 3-hydroxy steroid that is estra-1,3,5(10)-trien-3-ol substituted by additional hydroxy groups at positions 16 and 17 (16alpha,17beta-stereoisomer). A hydroxylated metabolite of estradiol or estrone that has a hydroxyl group at C3, 16-alpha, and 17-beta position. Estriol is a major urinary estrogen. During pregnancy, a large amount of estriol is produced by the placenta. Isomers with inversion of the hydroxyl group or groups are called epiestriol. E3 oestriol 17β-hydroxy steroid 3-hydroxy steroid The Complete Dictionary of Sexology