Establishment of pregnancy Flashcards
What needs to be blocked for pregnancy to be established?
Luteolysis must be blocked by preventing the formation of oxytocin receptors on the uterine endometrium
What is early conception factor?
Maternal response to zygote within hours of fertilisation
Bind to T-lymphocytes to protect developing embryo
Where and when is interferon tau (IFNT) produced?
expressed by trophectoderm cells
Expression initiated during trophoblast elongation
Stimulated by growth factors secreted from uterus in histotroph
Only expressed days 12-24 of pregnancy
What is the function of interferon tau (IFNT) in pregnancy?
Maternal recognition hormone
acts on the endometrium
suppresses oxytocin receptor expression => suppresses PGF2a secretion => maintains progesterone
Stimulates protein synthesis critical for embryo growth
antiviral
What is the maternal recognition hormone in pigs and how does it work?
Oestradiol
secreted just before implantation
re-direct flow of PGF2a away from uterine vein - secreted into uterine lumen rather than into uterine veins
What is the possible maternal recognition hormone in mares and how does it function?
Equine blastocyst:
- remains spherical and unattached: migration in uterus distributes MRP signal, stimulated by prostaglandins
- produces oestradiol
- produces proteins that suppress PGF2as production
What is the maternal recognition hormone in bitches and how does it function?
No MRP
pseudopregnancy
Embryo recognition in rodents
Mating leads to initial prolactin secretion (pregnancy or pseudogragnancy)
Lactogen from placenta takes over once prolactin secretion has finished if pregnant
When is maternal recognition of pregnancy in cows?
~ day 16
When is maternal recognition of pregnancy in ewes
~ day 13
When is maternal recognition of pregnancy in mares?
~ day 14
