INTERFERON, THE OXYTOCIN RECEPTOR AND THE MATERNAL RECOGNITION OF PREGNANCY IN RUMINANTS AND NONRUMINANTS - A COMPARATIVE APPROACH

Ruminant and non-ruminant members of the Artiodactyla appear to use different mechanisms for the maternal recognition of pregnancy. In ruminants, the trophoblast of the developing blastocyst produces a characteristic Type I interferon of the interferon-tau family; this acts by blocking endometrial synthesis of the oxytocin receptor. A similar mechanism applies to domestic ruminants (sheep, cow, goat) and deer. In roe deer, which have embryonic diapause and are monoestrus, there is no requirement for a pre-implantation blastocyst signal to ensure maternal recognition of pregnancy. This paper compares the mechanisms leading to the maternal recognition of pregnancy in ruminants with that suggested to occur in a non-ruminant (the domestic pig).