Isolation of a gonadotropin (PMEG) from pregnant mare endometrial cups: comparison with PMSG.

This research article discusses the isolation of a gonadotropin named PMEG from the endometrial cups in pregnant horses and how it compares to another gonadotropin, PMSG.

Research Methodology

• The researchers isolated the hormone PMEG from pregnant mare endometrial cups. Endometrial cups are temporary structures in the uterus of a pregnant horse. They’re an important part of equine pregnancy, secreting hormones that help to maintain the pregnancy.
• The same purification methodology applicable to PMSG, another hormone produced in pregnant horses, was used in the study.
• Once the PMEG was isolated and purified, the researchers carried out both in vivo (within a living organism) and in vitro (outside of a living organism, in a laboratory) assays for two types of gonadotropin hormones, FSH and LH, to evaluate the PMEG preparations.

Findings

• The researchers found that in all cases, the PMEG exhibited lower activities, between 11% and 54%, when compared to PMSG.
• An antiserum raised in rabbits against PMSG cross-reacted fully with PMEG, according to agar double diffusion tests. This suggests a similar immunological profile between PMEG and PMSG.
• The amino acid composition of PMEG was found to be similar to PMSG. However, it was determined that PMEG preparations were more heterogeneous than PMSG according to amino terminal group analyses.
• The carbohydrate composition of PMEG was considerably less, between 13% and 30%, than that found in PMSG, which was 45%. The lower carbohydrate composition might explain the lower activities of PMEG versus PMSG.

Implications

• These findings provide valuable insights into the hormonal composition of pregnant mares and could impact the hormonal management of horse reproduction. The differences in activities, immunological properties and composition between PMEG and PMSG could mean differing roles or efficiency levels in maintaining horse pregnancies.
• Additionally, the more heterogeneous nature of PMEG suggests that it might be less consistent in its effects or harder to measure precisely, which could affect its use in reproductive studies or applications.