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Domestic animal endocrinology2020; 74; 106562; doi: 10.1016/j.domaniend.2020.106562

Oxytocin receptor expression in stallion testes and epididymides.

Abstract: Endocrine, paracrine, and autocrine factors orchestrate the development and physiology of the stallion reproductive system. Oxytocin (OXT) is one of the critical endocrine, paracrine, and autocrine factors for the male reproductive system. Previous studies have investigated OXT receptor (OXTR) expression in testes and epididymides, including humans, marmosets, macaques, swine, and sheep. This study aimed to explore (1) OXTR localization in the testes and epididymides and (2) the seasonal modification of OXTR expression in the testes. Adult stallion testis and epididymis samples were prepared using routine castration procedures. Reverse-transcription PCR was performed to detect the presence of OXTR messenger RNA (mRNA) in the testes. Western blot procedure was performed to confirm the cross-reactivity of OXTR antibody to horse OXTR. Immunohistochemistry was performed to detect OXTR protein expression in the testes and epididymides. Oxytocin receptor mRNA was detected in the stallion testes. The OXTR protein band was observed at 55 kDa. Interestingly, the relative intensity of the OXTR protein band varied between nonbreeding and breeding season. The OXTR protein level in the testes collected during the breeding season was higher than that during the nonbreeding season. Oxytocin receptor localization was observed in the cytoplasm of Type A spermatogonia and spermatid. Oxytocin receptor protein expression was also observed in the cytoplasmic area of Leydig cells and the membrane of the seminiferous tubules. The cytoplasm of principal and basal cells in the caput, corpus, and cauda was also immunolabeled with OXTR antibody. In conclusion, based on the expression of OXTR in tissues of testes and epididymides, OXT-OXTR system may be a critical factor for stallion testicular and epididymal function. In addition, according to the seasonal alteration of intensity, the OXT-OXTR system may be associated with seasonal changes in the reproductive system in stallions.
Publication Date: 2020-09-12 PubMed ID: 33038836DOI: 10.1016/j.domaniend.2020.106562Google Scholar: Lookup
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  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

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This research explores the presence and seasonal variation of the oxytocin receptor (OXT) in the reproductive tissues of stallions. The study found OXT to be critical to the function of the stallion’s testes and epididymis and to change in concentration depending on the breeding season.

Research Objectives

  • The aim of this study was two-fold; first, it sought to determine the location of the oxytocin receptor (OXT) in stallion reproductive tissues (testes and epididymis), and second, to examine any seasonal changes in OXT expression in the testes.

Methodology

  • Adult stallion testis and epididymis samples were obtained using standard castration procedures.
  • OXT in the tissues was detected using reverse-transcription PCR to identify messenger RNA (mRNA).
  • A Western blot procedure was used to confirm the OXT antibody’s cross-reactivity with equine OXT.
  • Immunohistochemistry provided visual confirmation of the OXT protein’s presence in the testes and epididymides.

Findings

  • Oxytocin receptor mRNA was found in stallion testes, with the OXT protein band found at 55 kDa.
  • Interestingly, the study also found that the intensity of the OXT protein band varied seasonally, being more prevalent during the breeding season than the nonbreeding season.
  • Further, the localization of the OXT receptor was detected in the cytoplasm of Type A spermatogonia and spermatid, Leydig cells, and the membrane of seminiferous tubules in the testes. It was also found in the cytoplasm of principal and basal cells in the caput, corpus, and cauda of the epididymis.

Conclusion

  • Given the presence of OXT receptor in stallion reproductive tissues, it is suggested that the OXT system is critical for the functioning of the testes and epididymis in stallions.
  • The study also proposes that the OXT system may be associated with seasonal changes in the stallion’s reproductive system due to the observed variance in OXT receptor intensity.

Cite This Article

APA
Jung Y, Yoon M. (2020). Oxytocin receptor expression in stallion testes and epididymides. Domest Anim Endocrinol, 74, 106562. https://doi.org/10.1016/j.domaniend.2020.106562

Publication

ISSN: 1879-0054
NlmUniqueID: 8505191
Country: United States
Language: English
Volume: 74
Pages: 106562
PII: S0739-7240(20)30129-6

Researcher Affiliations

Jung, Y
  • Department of Animal Science and Biotechnology, Kyungpook National University, Sangju 37224, Republic of Korea.
Yoon, M
  • Department of Animal Science and Biotechnology, Kyungpook National University, Sangju 37224, Republic of Korea; Department of Horse, Companion and Wild Animal Science, Kyungpook National University, Sangju 37224, Republic of Korea. Electronic address: mjyoonemail@gmail.com.

MeSH Terms

  • Animals
  • Epididymis / metabolism
  • Gene Expression Regulation / physiology
  • Horses / metabolism
  • Male
  • Receptors, Oxytocin / genetics
  • Receptors, Oxytocin / metabolism
  • Seasons
  • Spermatogonia / metabolism
  • Testis / metabolism

Citations

This article has been cited 5 times.
  1. Shakeel M, Yoon M. Functions of somatic cells for spermatogenesis in stallions. J Anim Sci Technol 2022 Jul;64(4):654-670.
    doi: 10.5187/jast.2022.e57pubmed: 35969700google scholar: lookup
  2. Padilla L, López-Arjona M, Martinez-Subiela S, Rodriguez-Martinez H, Roca J, Barranco I. Oxytocin in pig seminal plasma is positively related with in vivo fertility of inseminated sows. J Anim Sci Biotechnol 2021 Sep 13;12(1):101.
    doi: 10.1186/s40104-021-00620-zpubmed: 34511116google scholar: lookup
  3. Mulyati S, Mustofa I, Susilowati S, Khairullah AR, Ahmad RZ, Akintunde AO, Pratama BP, Latifah L, Handayani UF, Anggraini L. Increasing the fertility of Sapudi sheep semen at 5°C storage temperature with the addition of oxytocin in a diluent of skim milk, egg yolk, and citrate. Open Vet J 2025 Sep;15(9):4700-4708.
    doi: 10.5455/OVJ.2025.v15.i9.74pubmed: 41200307google scholar: lookup
  4. Sahin H, Pashayeva F, Senturk GE. Oxytocin receptor expression in developing mouse gonads and its modulation by high-dose folic acid. J Mol Histol 2025 Oct 14;56(6):342.
    doi: 10.1007/s10735-025-10621-1pubmed: 41085722google scholar: lookup
  5. Garza-Brenner E, Sánchez-Dávila F, Mauleón-Tolentino K, Zapata-Campos CC, Luna-Palomera C, Hernandez-Melendez J, Gonzalez-Delgado M, Vázquez-Armijo JF. Systematic review of hormonal strategies to improve fertility in rams. Anim Reprod 2024;21(2):e20240007.
    doi: 10.1590/1984-3143-AR2024-0007pubmed: 38903866google scholar: lookup