Maternal Recognition of Pregnancy Flashcards
Know what maternal recognition of pregnancy (MRP) is.
-MRP is a biochemical signal that prevents luteolysis
-results in maintenance of pregnancy
When does MRP happen?
-Must occur before luteolysis begins
-first few days after fertilization
Why is MRP critical to pregnancy?
-If MRP does not occur luteolysis occurs and the embryo dies
Luteotropic
-functioning to increase the lifespan of the CL
-Usually acts directly on the CL
-Ex: Gonadotropin
Antiluteolytic
-functioning to prevent luteolysis by blocking the luteolytic factor
-Ex: inhibition of PGF2α secretion
How does MRP happen in the cow/ewe?
-Blastocyst produces bovine or ovine IFN-t (interferon-tau): Antiluteolytic produced by trophoblast cells between Day 10-21 of pregnancy
-Binds to endometrium -> blocks oxytocin receptor syntheses -> PGF2α
-Binds to apical portion of uterine glands -> produces proteins (uterine milk) that allow the embryo to grow
How does MRP happen in the sow?
-Conceptus begins to secrete estradiol between day 11-12 after ovulation
-Estradiol redirects PGF2α secretion towards the uterine lumen (PGF2α cannot enter the circulatory system easily here and luteolysis does not occur)
-Estradiol increases contraction to help push embryos into both horns
-At least two conceptus are requires in both horns (if not PGF2α is not redirected)
How does MRP happen in the mare?
-Unkown proteins and estrogen from conceptus reduces PGF2α
-The equine conceptus must move around the uterus by uterine contractions to distribute recognition factors
-Restricted movement results in higher termination rates
How does MRP happen in humans?
-Human conceptus secretes hCG
-hCG inhibits intraovarian luteolysis
MRP in cats and dogs
-Cats and dogs both have CL lifespans as long as gestation lengths
-CL on cats and dogs form after ovulation occurs
