Figure 1
From: Pregnancy recognition signaling mechanisms in ruminants and pigs
Interferon tau (IFNT) is the pregnancy recognition hormone in sheep and other ruminants that acts to silence expression of estrogen receptor alpha (ESR1) and, in turn, oxytocin receptor (OXTR) to prevent development of the luteolytic mechanism that required oxytocin (OXT) from the corpus luteum (CL) and posterior pituitary to induce luteolytic pulses of prostaglandin F 2α (PGF). Thus, IFNT blocks the ability of the uterus to develop the luteolytic mechanism, but does not inhibit prostaglandin synthase 2 (PTGS2) or the basal production of PGF during pregnancy.