Molecular characterization of equine P-selectin (CD62P) and its regulation in ovarian follicles during the ovulatory process Academic Article uri icon


MeSH Major

  • Estrous Cycle
  • Horses
  • Ovarian Follicle
  • P-Selectin


  • Ovulation is accompanied by a marked infiltration of leukocytes into thecal layers after the gonadotropin surge. P-selectin is known to play a critical role in the initial steps of leukocyte recruitment from the bloodstream during inflammation. Thus, the objective was to investigate the potential regulation of P-selectin by gonadotropins in equine preovulatory follicles. The full-length equine P-selectin cDNA was cloned by a combination of reverse transcription-polymerase chain reaction (RT-PCR) and 5'- and 3'-rapid amplification of cDNA ends. Results showed that equine P-selectin cDNA encodes an 829-amino acid protein that is highly conserved when compared to the human protein (80% identity). Semiquantitative RT-PCR/Southern blot analyses were performed to study the regulation of P-selectin transcript in preovulatory follicles isolated during estrus at 0, 12, 24, 30, 33, 36, and 39 h after an ovulatory dose of hCG (ovulation occurs between 39 and 42 h post-hCG in this model). Results showed that levels of P-selectin mRNA remained very low or undetectable throughout the ovulatory process in extracts prepared from the granulosa cell layer. In contrast, a significant increase in P-selectin transcript was observed between 30 and 39 h post-hCG in extracts obtained from thecal layers (P < 0.05). Likewise, immunohistochemistry revealed an increase of immunoreactive P-selectin protein in the vascular endothelium present in thecal layers of follicles isolated 36 and 39 h post-hCG. Thus, the present study describes, to our knowledge for the first time, the primary structure of equine P-selectin and the regulation of P-selectin transcript and protein in follicular thecal endothelial cells before ovulation.

publication date

  • March 2005



  • Academic Article



  • eng

Digital Object Identifier (DOI)

  • 10.1095/biolreprod.104.034710

PubMed ID

  • 15564599

Additional Document Info

start page

  • 736

end page

  • 44


  • 72


  • 3