The measurement of oestrone, equilin and dehydroepiandrosterone in the peripheral plasma of pregnant pony mares by radioimmunoassay.

This research article focuses on the measurement of three hormones—oestrone, equilin, and dehydroepiandrosterone—in the blood of pregnant pony mares, conducted via radioimmunoassay. The study aimed to track these hormone levels from the 60th day of pregnancy to parturition, and found that among the three, dehydroepiandrosterone showed the most consistent pattern, while there was significant variation in the levels of oestrone and equilin across different mares, and no clear link between elevated dehydroepiandrosterone levels and the secretion patterns of the two oestrogens.

Overview of the Study

• This research involved the measurement of oestrone, equilin, and dehydroepiandrosterone hormones in the peripheral blood plasma of five pony mares. The hormones were measured via a diagnostic technique known as radioimmunoassay.
• The research aimed at tracking the secretion patterns of these hormones from the 60th day of pregnancy up to the time of parturition (birth).

Findings of the Study

• Among the three hormones studied, dehydroepiandrosterone exhibited the most predictable pattern of secretion. Its concentrations remained low until the 105th day of pregnancy, after which they rapidly increased from day 120 before peaking between days 168–210. The levels then declined until day 300.
• However, there were considerable variations found in the patterns of dehydroepiandrosterone prior to parturition among the different mares.

Variations in Hormone Concentrations

• The research also identified significant variations in the relative concentrations of the two types of estrogen—oestrone and equilin—across the different mares.
• No clear relationship was established between the increased concentrations of dehydroepiandrosterone and the secretion pattern of the two types of oestrogen.

Implications of the Research

• The findings of this research help improve our understanding of the hormonal changes that occur in pony mares during pregnancy.
• This study might also help in diagnosing various reproductive and gestational issues in pony mares.
• The absence of a clear link between dehydroepiandrosterone concentrations and oestrogen secretion patterns suggests that other factors could be influencing their secretion during pregnancy.