221 Putative Gene Regulators in the Equine Endometrium, Corpus Luteum and Embryo During Early Pregnancy in the Horse

Abstract It is estimated that 17.3% of all pregnancies in the horse are lost from time detection to day 40, which has significant economic impact. But still, equine reproductive research limited funding opportunities. Understanding dynamics between embryo, endometrium, and corpus luteum (CL) essential ameliorate those losses. Pig embryonic interferon (IFN) gamma for establishment pregnancy. In ruminants, IFN tau maternal recognition signal. The embryo seems express alpha, gamma, delta, epsilon but higher expression was only identified on day(D) 16 embryos, after pregnancy (MRP), so role during unknown. Oxytocin prostaglandins have been demonstrated a luteolysis luteostasis horse, therefore investigation embryonic, CL putative gene regulators MRP warranted. Oxytocinase (LNPEP), an aminopeptidase metabolizes oxytocin (OXT) recently investigated with other expected MRP. OXT LNPEPmRNA were CL, OXT/neurophysin-1 protein not detected present CL. Most endometrial luteal mRNA differences around D12 post-ovulation, suggesting being critical Luteal different pregnant non-pregnant mares. LNPEP upregulated mares D10 12 tissues along prostaglandin E synthase (PTGES). Embryonic trophoblast PTGES relative abundance D15 conceptus compared earlier potential fixation. increased suggested decreasing availability shifting ratio PGE:PGF PGE will support function early