{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T18:41:12Z","timestamp":1788374472193,"version":"build-2803163510"},"reference-count":31,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2025,2,24]],"date-time":"2025-02-24T00:00:00Z","timestamp":1740355200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001691","name":"Ministry of Education, Science, Sports, and Culture, Grant in Aid for Scientific Research","doi-asserted-by":"publisher","award":["25304039"],"award-info":[{"award-number":["25304039"]}],"id":[{"id":"10.13039\/501100001691","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Animals","award":["25304039"],"award-info":[{"award-number":["25304039"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>Although yaks and cattle belong to the same Bovinae subfamily and have the same number of chromosomes, hybrid males are sterile because of the inactivation or abnormality of gene expression related to the production of healthy normal sperm. Recently, the analysis of gene expression not only in the testis but also in the epididymis has offered hints about the mechanism of infertility, because the epididymis supports the maturation of sperm in acquiring the capacity of fertilisation. Sperm maturation processes have been thought to be androgen-dependent, and the androgen receptor (AR) can be activated by dihydrotestosterone converted from plasma testosterone by the 5\u03b1-reductase isoform 2 (SRD5A2) in epididymal cells. In the present study, we investigated the immuno-expression levels of the AR and SRD5A2 in the epithelial cells of the hybrid cattle\u2013yak epididymal caput in comparison with yak samples using image analysis. Epididymal tissues from yaks (1\u20133 years of age) and hybrid cattle\u2013yaks (2 years of age) were used in this study. In yaks, AR signal intensity did not show any changes in epididymal epithelial cells during maturation. However, in 2-year-old hybrid cattle\u2013yaks, AR signal intensity was significantly higher in the principal cells of the epididymis compared to that of yaks of the same age, indicating that hybrid sterility is not likely related to AR deficiency in the epididymal epithelium. On the other hand, SRD5A2 signal intensity was stable during maturation in the epithelial cells of the yak epididymis. However, the epididymal SRD5A2 signal intensity in the epithelial cells of the hybrid cattle\u2013yak was lower than that of the yak. This suggests that a deficiency in SRD5A2 production in the epididymis may result in hybrid infertility, as it can subsequently cause incomplete AR signal transduction and altered spermatozoa physiology.<\/jats:p>","DOI":"10.3390\/ani15050660","type":"journal-article","created":{"date-parts":[[2025,2,25]],"date-time":"2025-02-25T06:13:18Z","timestamp":1740463998000},"page":"660","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Aberrant Expression Levels of Androgen Receptor and SRD5A2 in Epididymal Epithelial Cells of Crossbred Infertile Cattle\u2013Yak"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1646-0581","authenticated-orcid":false,"given":"Manita","family":"Wittayarat","sequence":"first","affiliation":[{"name":"Faculty of Veterinary Science, Prince of Songkla University, Songkhla 90110, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kimika","family":"Kawanishi","sequence":"additional","affiliation":[{"name":"Department of Medical Engineering, Faculty of Allied Sciences, University of East Asia, Yamaguchi 751-8503, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haruka","family":"Ohata","sequence":"additional","affiliation":[{"name":"Department of Medical Engineering, Faculty of Allied Sciences, University of East Asia, Yamaguchi 751-8503, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-7045-3922","authenticated-orcid":false,"given":"Megumi","family":"Nagahara","sequence":"additional","affiliation":[{"name":"Bio-Innovation Research Center, Tokushima University, Tokushima 779-3233, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rentsenkhand","family":"Sambuu","sequence":"additional","affiliation":[{"name":"Institute for Extension of Agricultural Advanced Technology, Ulaanbaatar 17024, Mongolia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4301-6726","authenticated-orcid":false,"given":"Otgonjargal","family":"Sambuu","sequence":"additional","affiliation":[{"name":"School of Veterinary Medicine, Mongolian University of Life Sciences, Ulaanbaatar 17024, Mongolia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4673-1581","authenticated-orcid":false,"given":"Maki","family":"Hirata","sequence":"additional","affiliation":[{"name":"Bio-Innovation Research Center, Tokushima University, Tokushima 779-3233, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2158-5808","authenticated-orcid":false,"given":"Fuminori","family":"Tanihara","sequence":"additional","affiliation":[{"name":"Bio-Innovation Research Center, Tokushima University, Tokushima 779-3233, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3422-1904","authenticated-orcid":false,"given":"Masayasu","family":"Taniguchi","sequence":"additional","affiliation":[{"name":"Department of Animal Reproduction, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi 753-0841, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0382-959X","authenticated-orcid":false,"given":"Takeshige","family":"Otoi","sequence":"additional","affiliation":[{"name":"Bio-Innovation Research Center, Tokushima University, Tokushima 779-3233, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1683-8505","authenticated-orcid":false,"given":"Yoko","family":"Sato","sequence":"additional","affiliation":[{"name":"Department of Medical Engineering, Faculty of Allied Sciences, University of East Asia, Yamaguchi 751-8503, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,2,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1111\/rda.13973","article-title":"High-throughput sequencing reveals differential expression of miRNAs in yak and cattleyak epididymis","volume":"57","author":"Wang","year":"2022","journal-title":"Reprod. 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