• Facets (new session)
• Description
• Metadata
• Settings
  • owl:sameAs
  • Inference Rule: b3sb3sifpdbprdf-labelfacetshttp://dbpedia.org/resource/inference/rules/dbpedia#http://dbpedia.org/resource/inference/rules/opencyc#http://dbpedia.org/resource/inference/rules/umbel#http://dbpedia.org/resource/inference/rules/yago#http://dbpedia.org/schema/property_rules#http://www.ontologyportal.org/inference/rules/SUMO#http://www.ontologyportal.org/inference/rules/WordNet#http://www.w3.org/2002/07/owl#ldpoplwebskos-transvirtrdf-labelNone
    

Preimplantation factor (PIF) is a peptide secreted by trophoblast cells prior to placenta formation in early embryonic development. Human embryos begin to express PIF at the 4-cell stage, with expression increasing by the morula stage and continuing to do so throughout the first trimester. Expression of preimplantation factor in the blastocyst was discovered as an early correlate of the viability of the eventual pregnancy. Preimplantation factor was identified in 1994 by a lymphocyte platelet-binding assay, where it was thought to be an early biomarker of pregnancy. It has a simple primary structure with a short sequence of fifteen amino acids without any known quaternary structure. A synthetic analogue of preimplantation factor (commonly abbreviated in studies as sPIF or PIF*) that has an