Effect of PGF2alpha and 13,14-dihydro-15-keto-PGF2alpha (PGFM) on corpora luteal function in nonpregnant mares.

The research study investigates whether the primary circulating metabolite of PGF2alpha, known as 13,14-dihydro-15-keto-PGF2alpha or PGFM, has biological activity and can induce luteolysis in nonpregnant mares. The findings do not support the idea that PGFM is biologically active in mares, as it did not change the function of the horse’s corpus luteum.

Methodology and Experiment Setup

• The experiment was designed around the ninth day after ovulation. Mares were randomly assigned to three groups of seven for different treatments:
  • First group served as the control group and were given a saline solution.
  • Second group were treated with 10 mg PGF2alpha.
  • Third group were treated with 10 mg PGFM.
• Blood samples were taken regularly over a period of 16 days, before and after treatment, for analysis of progesterone levels as well as PGFM levels.

Results and Findings

• Luteolysis, or the degradation of the corpus luteum, only occurred in the mares treated with PGF2alpha and not in the control group or in the mares treated with PGFM.
• There were no significant differences (P>0.1) in the occurrence of luteolysis in control and PGFM-treated mares, while more PGF2alpha-treated mares underwent luteolysis.
• Progesterone concentrations did not differ significantly between the control group and the PGFM-treated mares from Days 10 to 16. However, the PGF2alpha-treated mares had lower progesterone levels.
• Lastly, there were no noteworthy differences (P>0.05) in PGFM concentrations between mares treated with PGF2alpha and PGFM; the PGFM levels in both groups were higher than in the control group.

Conclusion

• The results do not provide evidence that PGFM is biologically active in mares as it did not affect the function of the corpus luteum, unlike the treatment with PGF2alpha.
• This suggests that PGFM may not play a significant role in inducing luteolysis in nonpregnant mares.