Effect of pulsatile gonadotrophin release on mean serum LH and FSH in peri-parturient mares.

The research paper studies the changes in the pattern of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the blood of mares around childbirth. It reveals that mares show simultaneous pulses of FSH and LH before foaling, these pulses become more frequent on the day of foaling, and increase the mean value of FSH but not LH.

Objectives and Methodology

• The main aim of the study was to understand the changes and relationship between LH and FSH during the period surrounding childbirth (peri-parturient) in mares.
• The study involved 6 mares and observed hormone levels at regular intervals before and after childbirth.
• Blood samples were taken every 15 minutes over a 24-hour period at two points before childbirth, and at 12-hour intervals on the day of childbirth (Day 0) and 4 days after childbirth (Day 4).

Results and Findings

• Simultaneous and infrequent pulses of both LH and FSH occurred before childbirth.
• On the day of childbirth, the frequency of these pulses significantly increased, indicating a potential relationship between these hormones and the process of foaling.
• The amplitude (or peak level) of these pulses was found to be higher before childbirth, suggesting a need for a high level of these hormones leading up to this event.
• The presence of FSH pulses increased the mean (or average) value of FSH on the days when these pulses were detected, including on the day of birth.
• A different pattern was observed for LH, where detectable pulses were not associated with an increase in the mean LH value.

Conclusions and Implications

• The study concludes that LH and FSH release is pulsatile (occurs in pulses) in the mare around childbirth. This suggests a potential link between these hormone pulses and the process of childbirth.
• The researchers note that the increased mean FSH value when pulses occur, as opposed to no similar change in LH, might point towards a one hypothalamic releasing hormone for both LH and FSH in mares.
• This insight could add to our understanding of hormone regulation during childbirth in mares, potentially leading to better reproductive management practices in equine breeding.