<?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%">Baltrusaitis, Jonas</style></author><author><style face="normal" font="default" size="100%">Patterson, Eric V.</style></author><author><style face="normal" font="default" size="100%">O'Connor, Meghan</style></author><author><style face="normal" font="default" size="100%">Qu, Shen</style></author><author><style face="normal" font="default" size="100%">Kolodziej, Edward P.</style></author><author><style face="normal" font="default" size="100%">Cwiertny, David M.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Reversible Photohydration of Trenbolone Acetate Metabolites: Mechanistic Understanding of Product-to-Parent Reversion through Complementary Experimental and Theoretical Approaches.</style></title><secondary-title><style face="normal" font="default" size="100%">Environmental Science &amp; Technology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">trenbolone acetate metabolite reversible photohydration mechanism</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2016</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2016</style></date></pub-dates></dates><publisher><style face="normal" font="default" size="100%">American Chemical Society</style></publisher><volume><style face="normal" font="default" size="100%">50</style></volume><pages><style face="normal" font="default" size="100%">6753 - 6761</style></pages><isbn><style face="normal" font="default" size="100%">0013-936X</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Photolysis expts. (in H2O and D2O) and quantum chem. calcns. were performed to explore the pH-dependent, reversible photohydration of trenbolone acetate (TBA) metabolites.  Photohydration of 17α-trenbolone (17α-TBOH) and 17β-trenbolone (17β-TBOH) occurred readily in simulated sunlight to yield hydrated products with incorporated H+ at C4 and OH- at either C5 (5-OH-TBOH) or C12 (12-OH-TBOH) in the tetracyclic steroid backbone.  Although unable to be elucidated anal., theory suggests preferred orientations of cis-12-OH-TBOH (relative to C13 methyl) and trans-5-OH-TBOH, with the former most thermodynamically stable overall.  Both expt. and theory indicate limited stability of trans-5-OH-TBOH at acidic pH where it undergoes concurrent, carbocation-mediated thermal rearrangement to cis-12-OH-TBOH and dehydration to regenerate its parent structure.  Expts. revealed cis-12-OH-TBOH to be more stable at acidic pH, which is the only condition where its reversion to parent TBA metabolite occurred.  At basic pH cis-12-OH-TBOH decayed quickly via hydroxide/water addn., behavior that theory attributes to the formation of a stable enolate resistant to dehydration but prone to thermal hydration.  In a noteworthy deviation from predicted theor. stability, 17α-TBOH photohydration yields major trans-5-OH-TBOH and minor cis-12-OH-TBOH, a distribution also opposite that obsd. for 17β-TBOH.  Because H+ and OH- loss from adjacent carbon centers allows trans-5-OH-TBOH to dehydrate at all pH values, the presumed kinetically controlled yield of 17α-TBOH photohydrates results in a greater propensity for 17α-TBOH reversion than 17β-TBOH.  Addnl. calcns. explored minor, but potentially bioactive, trenbolone analogs that could be generated via alternative rearrangement of the acidic carbocation intermediate. [on SciFinder(R)]</style></abstract><issue><style face="normal" font="default" size="100%">13</style></issue><notes><style face="normal" font="default" size="100%">CAPLUS AN 2016:126331(Journal; Online Computer File)</style></notes></record><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%">Kolodziej, Edward P.</style></author><author><style face="normal" font="default" size="100%">Qu, Shen</style></author><author><style face="normal" font="default" size="100%">Forsgren, Kristy L.</style></author><author><style face="normal" font="default" size="100%">Long, Sarah A.</style></author><author><style face="normal" font="default" size="100%">Gloer, James B.</style></author><author><style face="normal" font="default" size="100%">Jones, Gerrad D.</style></author><author><style face="normal" font="default" size="100%">Schlenk, Daniel</style></author><author><style face="normal" font="default" size="100%">Baltrusaitis, Jonas</style></author><author><style face="normal" font="default" size="100%">Cwiertny, David M.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Identification and Environmental Implications of Photo-Transformation Products of Trenbolone Acetate Metabolites.</style></title><secondary-title><style face="normal" font="default" size="100%">Environmental Science &amp; Technology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">photodegrdn trenbolone acetate metabolite Oryzias ecotoxicity</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year></dates><publisher><style face="normal" font="default" size="100%">American Chemical Society</style></publisher><volume><style face="normal" font="default" size="100%">47</style></volume><pages><style face="normal" font="default" size="100%">5031 - 5041</style></pages><isbn><style face="normal" font="default" size="100%">0013-936X</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Despite the widespread use of the anabolic androgen trenbolone acetate (TBA) in animal agriculture, evidence demonstrating the occurrence of TBA metabolites such as 17β-trenbolone (17β-TBOH), 17α-trenbolone (17α-TBOH), and trendione (TBO) is relatively scarce, potentially due to rapid transformation processes such as direct photolysis.  Therefore, we investigated the phototransformation of TBA metabolites and assocd. ecol. implications by characterizing the photoproducts arising from the direct photolysis of 17β-TBOH, 17α-TBOH, and TBO and their assocd. ecotoxicity.  LC-HRMS/MS anal. identified a range of hydroxylated products that were no longer photoactive, with primary photoproducts consisting of monohydroxy species and presumptive diastereomers.  Also obsd. were higher-order hydroxylated products probably formed via subsequent reaction of primary photoproducts.  NMR anal. confirmed the formation of 12,17-dihydroxy-estra-5(10),9(11),dien-3-one (12-hydroxy-TBOH; 2.2 mg), 10,12,17-trihydroxy-estra-4,9(11),dien-3-one (10,12-dihydroxy-TBOH; 0.7 mg), and a ring-opened 11,12-dialdehyde oxidn. product (TBOH-11,12-dialdehyde; 1.0 mg) after irradn. of ∼14 mg of 17β-trenbolone.  Though unconfirmed by NMR, our data suggest that the formation of addnl. isomeric products may occur, likely due to the reactivity of the unique 4,9,11 conjugated triene structure of trenbolone.  In vivo exposure studies employing Japanese medaka (Oryzias latipes) indicate that low concns. of 17α-TBOH photoproduct mixts. can alter ovarian follicular development, and photoproducts alter whole-body 17β-estradiol levels.  Therefore, direct photolysis yields photoproducts with strong structural similarity to parent steroids, and these photoproducts still retain enough biol. activity to elicit observable changes to endocrine function at trace concns.  These data indicate that environmental transformation processes do not necessarily reduce steroid hormone ecotoxicity. [on SciFinder(R)]</style></abstract><issue><style face="normal" font="default" size="100%">10</style></issue><notes><style face="normal" font="default" size="100%">CAPLUS AN 2013:623700(Journal; Online Computer File)</style></notes></record><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%">Qu, Shen</style></author><author><style face="normal" font="default" size="100%">Kolodziej, Edward P.</style></author><author><style face="normal" font="default" size="100%">Long, Sarah A.</style></author><author><style face="normal" font="default" size="100%">Gloer, James B.</style></author><author><style face="normal" font="default" size="100%">Patterson, Eric V.</style></author><author><style face="normal" font="default" size="100%">Baltrusaitis, Jonas</style></author><author><style face="normal" font="default" size="100%">Jones, Gerrad D.</style></author><author><style face="normal" font="default" size="100%">Benchetler, Peter V.</style></author><author><style face="normal" font="default" size="100%">Cole, Emily A.</style></author><author><style face="normal" font="default" size="100%">Kimbrough, Kaitlin C.</style></author><author><style face="normal" font="default" size="100%">Tarnoff, Matthew D.</style></author><author><style face="normal" font="default" size="100%">Cwiertny, David M.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Product-to-parent reversion of trenbolone: Unrecognized risks for endocrine disruption.</style></title><secondary-title><style face="normal" font="default" size="100%">Science (Washington, DC, United States)</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">trenbolone metabolite reversion endocrine disruption environment risk</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year></dates><publisher><style face="normal" font="default" size="100%">American Association for the Advancement of Science</style></publisher><volume><style face="normal" font="default" size="100%">342</style></volume><pages><style face="normal" font="default" size="100%">347 - 351</style></pages><isbn><style face="normal" font="default" size="100%">0036-8075</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Trenbolone acetate (TBA) is a high-value steroidal growth promoter often administered to beef cattle, whose metabolites are potent endocrine-disrupting compds.  We performed lab. and field phototransformation expts. to assess the fate of TBA metabolites and their photoproducts.  Unexpectedly, we obsd. that the rapid photohydration of TBA metabolites is reversible under conditions representative of those in surface waters (pH 7, 25°C).  This product-to-parent reversion mechanism results in diurnal cycling and substantial regeneration of TBA metabolites at rates that are strongly temp.- and pH-dependent.  Photoproducts can also react to produce structural analogs of TBA metabolites.  These reactions also occur in structurally similar steroids, including human pharmaceuticals, which suggests that predictive fate models and regulatory risk assessment paradigms must account for transformation products of high-risk environmental contaminants such as endocrine-disrupting steroids. [on SciFinder(R)]</style></abstract><issue><style face="normal" font="default" size="100%">6156</style></issue><notes><style face="normal" font="default" size="100%">CAPLUS AN 2013:1616444(Journal)</style></notes></record></records></xml>