Plasma progesterone concentrations derived from the administration of exogenous progesterone to ovariectomized mares.

The research primarily studied the impacts of administered exogenous progesterone on blood progesterone levels in mares who’ve undergone ovariectomy, split into three groups. They found that, depending on dosage and type, progesterone levels were sustained at varying levels for extended periods.

Study Methodology

• For this study, six mares that had been ovariectomized were employed as the test subjects. They were divided into three groups.
• Two forms of progesterone were used: progesterone in oil and repositol progesterone.
• The researchers conducted multiple experiments (Exp. I and II). In the first experiment, progesterone in oil was administered via seven daily injections.
• In the second experiment, repositol progesterone was administered on the first and seventh days.

Observations and Outcomes

• The study showed that a daily dosage of 50 mg of progesterone in oil did not manage to maintain progesterone levels in the plasma above 1.0 ng/ml for a period of 24 hours.
• At a daily dosage of 100 mg, however, plasma progesterone levels remained above 1.0 ng/ml for the last four days of the injection sequence.
• A dose of 200 mg per day maintained progesterone levels above 1.5 ng/ml throughout the entire sequence of injections.
• On day one and seven, 500 mg of repositol progesterone caused progesterone levels to peak after 6 hours but return to nearly 1.0 ng/ml after two days.
• Plasma progesterone levels were maintained for seven days following a single injection of either 1000 mg or 2000 mg of repositol progesterone on day one. They reached approximately 2.0 ng/ml and 4.0 ng/ml respectively, for these doses.
• 11 days after the injection on day seven, plasma progesterone levels stood at 1.5 ng/ml and 3.5 ng/ml for 1000 mg and 2000 mg doses respectively.

Conclusions

• A cumulative effect on plasma progesterone levels was noticed after continuous doses of both progesterone types, indicating that their effects accumulate over time.
• The research demonstrates that the type and dosage of progesterone administered can greatly influence the plasma progesterone concentrations in mares who’ve undergone ovariectomy – with higher doses and repositol progesterone maintaining higher levels for longer durations.