{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,24]],"date-time":"2026-08-24T19:37:15Z","timestamp":1787600235388,"version":"build-2736575974"},"reference-count":51,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2026,3,1]],"date-time":"2026-03-01T00:00:00Z","timestamp":1772323200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004442","name":"National Science Centre, Poland","doi-asserted-by":"publisher","award":["2023\/07\/X\/NZ9\/01407"],"award-info":[{"award-number":["2023\/07\/X\/NZ9\/01407"]}],"id":[{"id":"10.13039\/501100004442","id-type":"DOI","asserted-by":"publisher"}]},{"name":"The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>The present study investigated the impact of microplastics, specifically polystyrene microparticles (PS-MP), on the hypothalamic-pituitary-gonadal (HPG) neurohormonal axis, which regulates reproductive functions in animals and humans. The primary objective was to examine the effects of PS-MP on the expression of key genes and hormone concentrations within the gonadotropic system of sheep. Two doses of PS-MP\u2014the lower dose (LD; 0.015 mg\/kg) and the higher dose (HD; 0.15 mg\/kg)\u2014were administered intravenously every three days over two estrous cycles (34 days). Both doses significantly decreased the relative abundance of gonadotropin-releasing hormone (GnRH) transcripts in the mediobasal hypothalamus (MBH), whereas only the HD reduced GnRH mRNA levels in the preoptic area (POA). These transcript-level changes were not accompanied by detectable alterations in GnRH protein concentration. In the MBH, the expression of kisspeptin (KISS-1) and neurokinin B (NKB) genes decreased following exposure to the HD, whereas in the POA, significant decrease in expression were observed only after the LD administration. Changes in prodynorphin (PDYN) gene expression were confined to the MBH and were dose-dependent: the LD increased transcript levels, whereas the HD caused a decrease. The HD of PS-MP also significantly downregulated GnRH receptor (GnRHR) expression in the anterior pituitary (AP). Both PS-MP doses resulted in marked reductions in luteinizing hormone beta (LH\u03b2) and follicle-stimulating hormone beta (FSH\u03b2) subunit gene expression in the AP, without significant changes in hormone protein concentrations. Exposure to PS-MP reduced plasma LH and FSH concentrations: the lower dose reduced both hormones, while the higher dose significantly reduced mainly FSH, showing statistical differences between doses. To summarize, the present study demonstrates that PS-MP exerts a modulatory effect on the secretory activity of the central reproductive system in sheep, at both the hypothalamic and pituitary levels. Consequently, PS-MP has the potential to induce significant disruptions to the reproductive processes of large farm animals.<\/jats:p>","DOI":"10.3390\/ijms27052316","type":"journal-article","created":{"date-parts":[[2026,3,2]],"date-time":"2026-03-02T12:39:56Z","timestamp":1772455196000},"page":"2316","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Effects of Microplastics on the Central Reproductive Neuroendocrine System in a Sheep Model"],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5676-1373","authenticated-orcid":false,"given":"Patrycja","family":"M\u0142otkowska","sequence":"first","affiliation":[{"name":"Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3 St., 05-110 Jablonna, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2873-5597","authenticated-orcid":false,"given":"Bartosz","family":"Osuch","sequence":"additional","affiliation":[{"name":"Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3 St., 05-110 Jablonna, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"El\u017cbieta","family":"Marciniak","sequence":"additional","affiliation":[{"name":"Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3 St., 05-110 Jablonna, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dorota Anna","family":"Zi\u0119ba","sequence":"additional","affiliation":[{"name":"Department of Animal Biotechnology, Faculty of Animal Science, University of Agriculture, Al. Mickiewicza 24\/28, 31-059 Krak\u00f3w, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3054-7651","authenticated-orcid":false,"given":"Adrianna","family":"Konopka","sequence":"additional","affiliation":[{"name":"Laboratory of Analysis of Gastrointestinal Tract Protective Barrier, Department of Animal Nutrition, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3 St., 05-110 Jablonna, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2556-4983","authenticated-orcid":false,"given":"Tomasz","family":"Misztal","sequence":"additional","affiliation":[{"name":"Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3 St., 05-110 Jablonna, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"768","DOI":"10.1126\/science.1260352","article-title":"Marine pollution. 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