The nerve of ovulation-inducing factor in semen

Area of Science:

• Reproductive Biology
• Endocrinology
• Molecular Biology

Background:

• Seminal fluid contains a factor that induces ovulation, but its identity and mechanism remain largely unknown.
• The ovulation-inducing factor (OIF) has broad implications for reproductive biology and infertility.
• Understanding OIF's identity is crucial for exploring its role across species and clinical relevance.

Purpose of the Study:

• To identify the ovulation-inducing factor (OIF) present in seminal plasma.
• To test the hypothesis that OIF is a single, conserved biological entity.
• To elucidate the mechanism of OIF action on the female reproductive axis.

Main Methods:

• Column chromatography was used to isolate OIF from llama seminal plasma.
• Mass spectrometry (MALDI-TOF) and X-ray diffraction determined OIF's molecular mass, sequence, and structure.
• In vitro assays (PC(12) cells) and in vivo studies (llama ovulation) assessed OIF's biological activity and NGF-like properties.

Main Results:

• OIF was identified as beta nerve growth factor (β-NGF), a highly conserved protein.
• β-NGF demonstrated NGF-like properties, including neurite development and trkA up-regulation.
• Administration of β-NGF induced ovulation in llamas, confirming its role as OIF.

Conclusions:

• The ovulation-inducing factor (OIF) in seminal plasma is beta nerve growth factor (β-NGF).
• β-NGF is highly conserved across species and acts via an endocrine pathway.
• This discovery reveals a novel mechanism for male influence on the female hypothalamo-pituitary-gonadal axis.