[Endogenous opioids and their effects on reproduction] effects]

Area of Science:

• Reproductive endocrinology
• Animal physiology

Background:

• Endogenous opioid peptides (EOPs) play a role in regulating reproductive processes.
• Stress is known to influence hormonal pathways involved in reproduction.

Purpose of the Study:

• To review the regulatory actions of EOPs on gonadotropin secretion in livestock.
• To examine stress-induced alterations in EOPs and their impact on reproductive functions.

Main Methods:

• Literature review of studies on sheep, pigs, and cattle.
• Analysis of research on opioid peptide signaling in the hypothalamic-pituitary-gonadal axis.

Main Results:

• EOPs modulate gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) secretion.
• Stress elevates endogenous opioid levels, leading to suppressed gonadotropin release and impaired reproductive capacity.

Conclusions:

• Endogenous opioids are key regulators of reproductive endocrinology in livestock.
• Managing stress is crucial for maintaining optimal reproductive performance in farm animals.