The estrogens of the pregnant mare.

This research article explores the main estrogen components in pregnant mares, discovering that estrone and equilin are the primary constituents, while equilenin is a minor one. The study also outlines a chromatographic method for the separation of these estrogens in the urine of the horses.

Objective and Methodology

• The main objective of the research was to understand more about the types and levels of estrogens in pregnant mares.
• The researchers tracked the urinary ketonic estrogens in five pregnant mares at monthly intervals.
• Researchers also developed a partition chromatographic method to separate the ketonic phenolic steroids found in pregnant mares’ urine.

Key Findings

• The study found that the principal components of the mares’ estrogens are estrone and equilin, while equilenin is a less common component.
• The researchers discovered that the levels of equilin rise from the 4th or 5th months of pregnancy and in some cases, even surpass the levels of estrone in the later months of pregnancy.

Implications and Conclusions

• This research provides valuable information on the hormonal changes in mares during pregnancy, particularly about the levels and types of estrogens, which are important hormones for the maintenance and growth of the pregnancy.
• The increment of equilin levels over estrone in the later stages of pregnancy indicates some specific physiological needs or adjustments during those stages.
• The chromatographic method developed in this study for separating the estrogens in mares’ urine can facilitate further studies on hormonal variations and their effects in pregnant mares, as well as other animals.