Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.5/7178
Título: Coumestrol and its metabolite in mares' plasma after ingestion of phytoestrogen rich plants : potent endocrine disruptors inducing infertility
Autor: Ferreira-Dias, G.
Botelho, M.
Zagrajczuk, A.
Rebordão, M.R.
Galvão, A.M.
Bravo, P. Pinto
Piotrowska-Tomala, K.
Szóstek, A.Z.
Wiczkowski, W.
Piskula, M.
Fradinho, M.J.
Skarzynski, D.J.
Palavras-chave: Phytoestrogens
Clover-mixed pastures
Data: 1-Out-2013
Editora: Elsevier Inc.
Citação: Ferreira-Dias, G., et al. (2013). Coumestrol and its metabolite in mares' plasma after ingestion of phytoestrogen rich plants : potent endocrine disruptors inducing infertility. Theriogenology, 80(6), 684–692. doi: 10.1016/j.theriogenology.2013.06.002
Resumo: Phytoestrogens exist in plants that are present in forages fed to horses. They may compete with 17-β estradiol and influence the estrous cycle. Therefore, the objective was to determine whether coumestrol from clover-mixed pastures is present in mare's plasma after their ingestion (experiment I), and when this phytoestrogen was present in mare's plasma after ingestion (experiment II). The effect of a long-term ingestion of phytoestrogens on estrous cycle disruption was assessed (experiment III; clinical case). Experiment I was carried out in nonpregnant anestrous and cyclic Lusitano mares (n = 14) kept on clover and grass-mixed pastures, and supplemented with concentrate and hay or cereal straw. Blood and feedstuff were obtained from November to March. In experiment II, stabled cyclic Lusitano mares (n = 6) were fed for 14 days with increasing amounts of alfalfa pellets (250 g to 1 kg/day). Sequential blood samples were obtained for 8 hours after feed intake on Day 0 (control) and on Days 13 and 14 (1 kg/day alfalfa pellets). Experiment III mares were fed with a mixture of alfalfa and clover haylage for 5 months (group 1; n = 4) or for 9 months (group 2; n = 12). Estrous cycle was determined on the basis of plasma estradiol (E2), progesterone (P4), and ultrasound (experiment III). Concentrations of phytoestrogen coumestrol and its metabolite methoxycoumestrol were determined by high-performance liquid chromatography coupled with mass spectrometry. Phytoestrogens decreased in pasture from November until March (P < 0.01) (experiment I), but were always detected in mares' plasma. In experiment II, plasma-conjugated forms of coumestrol and methoxycoumestrol were higher on Days 13 and 14 than in control (P < 0.05). The highest concentrations of conjugated form of coumestrol were at 1.5 and 4 hours (P < 0.001), whereas its free forms peaked at 1 and at 3.5 hours after ingestion (P < 0.05). Methoxycoumestrol-conjugated form concentration was the highest at 1.5 and 5 hours (P < 0.001), whereas its free form peaked at 1 hour (P < 0.05) and at 1.5 hours (P < 0.001). Long-term intake of coumestrol caused lack of ovulation, uterine edema, and uterine fluid accumulation (experiment III). Coumestrol and methoxycoumestrol in both forms were higher in group 2 (while still ingesting haylage) than in group 1, after haylage withdrawal (P < 0.001). These data show that in the mare, coumestrol and its metabolite increase in blood after ingestion of estrogenic plants and can influence reproduction in mares as potent endocrine disruptors.
Descrição: Articles in International Journals
Peer review: yes
URI: http://hdl.handle.net/10400.5/7178
DOI: 10.1016/j.theriogenology.2013.06.002
ISSN: 0093-691X
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