Periovulatory changes in peripheral plasma progesterone and estrogen concentrations in the mare.

The research investigates changes in the concentrations of progesterone and estrogen in the mare’s blood around the period of ovulation. The study revealed that progesterone levels increase after ovulation while estrogen levels remain constant.

Methodology

• The study involved measuring the concentrations of the hormones progesterone and estrogen in the mare’s peripheral blood plasma samples. This sampling was done around the time of ovulation.
• The scientists collected these samples every two hours, from 36 hours before ovulation to 26 hours after.
• The concentrations of the hormones were assessed using a method known as radioimmunoassay, a technique that uses radioactivity to measure the concentrations of various substances within a sample.

Key Findings

• The results showed that progesterone levels were between 60 and 100 pg/ml a day before ovulation until 8 hours after. This suggests that progesterone levels remain relatively stable around the time of ovulation.
• However, progesterone concentrations began to increase 10 hours after ovulation, reaching 140 pg/ml, and hit 346 pg/ml by 26 hours after ovulation. This indicates that progesterone concentrations in the mare significantly rise only after ovulation.
• In contrast, the estrogen levels did not show any significant change during the same period. This suggests that estrogen levels may not vary much with the ovulation cycle.

Conclusion

• The research provides evidence that progesterone and estrogen hormones exhibit different patterns around the time of ovulation in mares. More specifically, progesterone concentrations increase significantly after ovulation, while estrogen concentrations remain relatively constant.