Oxytocin and PGF2alpha release in mares resistant and susceptible to persistent mating-induced endometritis.

The research explores how oxytocin (a hormone related to childbirth) and a prostaglandin metabolite react after artificial insemination in mares (female horses) that are resistant and susceptible to a particular kind of endometritis, which can be triggered by mating. The researchers suggest that the susceptible group might have some kind of defect at the oxytocin receptor level.

Research Background

• The study focused on comparing two groups of mares: ones resistant (7) and ones susceptible (9) to persistent mating-induced endometritis following artificial insemination (AI) during estrus (a period in the mare’s reproductive cycle).
• Oxytocin and the metabolite of prostaglandin F2alpha, 13,14-dihydro-15-keto PGF2alpha (PGFM), were the primary compounds investigated in this research.

Research Methodology

• Blood samples were taken from the mares starting 30 minutes before AI, continuing for 2 hours after, and again between 16 and 18 hours after AI.
• The samples were tested to ascertain oxytocin and PGFM concentrations.
• In the second experiment, a given amount of oxytocin was intravenously provided to both resistant and susceptible mares, with the aftermath of the administration being carefully recorded.

Research Findings

• The AI process resulted in a significant increase in oxytocin levels in both the resistant and susceptible mares, and no significant variation in oxytocin release was noted between the two groups.
• However, the average PGFM levels in the resistant group were significantly higher in the first 30 minutes following AI.
• The second experiment revealed that the administration of oxytocin resulted in a more profound release of PGF2alpha in resistant mares than in susceptible mares.

Conclusion and Implications

• The pattern of decreased PGFM concentrations in the susceptible group after both AI and oxytocin administration suggests a potential defect in PGF2alpha release. This could be at the level of the oxytocin receptor or after it.
• These findings could guide further research into the possible causes of endometritis in horses and could provide valuable insights for animal reproductive health.