The extracellular vesicles of boar seminal plasma contain oxytocin at levels associated with fertility

Written By : Dr. Kamal Kant Kohli Published On 2026-01-12T20:00:53+05:30 | Updated On 12 Jan 2026 8:00 PM IST

The presence of oxytocin (OXT) in seminal plasma is related to the fertility outcomes of male pigs used in artificial insemination (AI) programs. However, OXT rapidly volatilizes when circulating freely in body fluids, making it challenging to understand how it maintains its functional activity in refrigerated AI semen doses. These doses are usually stored for several days before use. One possible explanation is that seminal OXT circulates in extracellular vesicles (EVs), which are abundant in seminal plasma and prevent volatilization. This study aims to test this hypothesis.

Seminal EVs were isolated by size-exclusion chromatography from ejaculates of male pigs used in artificial insemination (AI) programs. The seminal EVs were characterized according to the International Society of Extracellular Vesicles guidelines (MISEV2023). OXT levels were measured using a direct competitive immunoassay based on AlphaLISA technology and an anti-OXT monoclonal antibody.

The results showed that male pig seminal EVs carry OXT, which is primarily located on the outer surface of the EV membrane, likely within the protein corona. Seminal EVs from the accessory sex glands were particularly enriched in OXT. The levels of oxytocin (OXT) in seminal EVs were related to the fertility of male pigs. Specifically, OXT levels were positively associated with the farrowing rate of inseminated sows, but negatively associated with the number of piglets born per litter. This ambivalence may reflect the proposed role of seminal OXT-containing EVs in stimulating myometrial contractility. This would improve sperm transport and fertilization, but hinder embryo implantation.

Reference

Parra A, Martínez-Díaz P, Botía M, López-Arjona M, Lucas X, Barranco I, Roca J. The extracellular vesicles of boar seminal plasma contain oxytocin at levels associated with fertility. Extracell Vesicles Circ Nucleic Acids. 2025;6:1000-14. https://dx.doi.org/10.20517/evcna.2025.94

Source : Extracellular Vesicles and Circulating Nucleic Acids

Dr. Kamal Kant Kohli

Dr Kamal Kant Kohli-MBBS, DTCD- a chest specialist with more than 30 years of practice and a flair for writing clinical articles, Dr Kamal Kant Kohli joined Medical Dialogues as a Chief Editor of Medical News. Besides writing articles, as an editor, he proofreads and verifies all the medical content published on Medical Dialogues including those coming from journals, studies,medical conferences,guidelines etc. Email: drkohli@medicaldialogues.in. Contact no. 011-43720751