Maternal Recognition of Pregnancy

Question 1

What does the corpus luteum need to stay viable?

Answer 1

-hCG (human choriogonadotropin)= lutenizing hormone produced by embryo
**Other mammals, don’t use LH. The corpus luteum will survive until receives signal to die= PGF2alpha (produced by uterus)

Question 2

Fetus and PGF2alpha

Answer 2

-Fetus prevents release of the PGF2alpha to ensure corpus luteum survives and maintains pregnancy

Question 3

Vaginal semen deposition

Answer 3

-humans, rabbits, rats, cows, dogs, cats
>cervix is open in dog and cats so could be uterine semen deposition

Question 4

Uterine semen deposition

Answer 4

-llamas, camelids, horse, pigs,
-artificial insemination

Question 5

Copulatory plugs and gels

Answer 5

-cervical cap in guinea pig, rats, mice
-human semen coagulates into loos gel
-camelid semen coagulates
-dogs use penis as plug

Question 6

Non-pregnant cycle in cattle

Answer 6

-Corpus luteum grows until ~10 days where it begins to regress when progesterone stops being produced when no pregnancy detected and uterus released PGF2alpha
-follicles grow and regress in cycles continuously throughout the cycle

Question 7

Pregnant cycle in cattle

Answer 7

-Corpus luteum will continue to grow because received embryo signal and does not receive PGF2alpha from uterus
-Follicles dominant and regress in waves

Question 8

Maternal recognition of pregnancy

Answer 8

-involves biochemical communication between the conceptus and its mother to provide uninterrupted synthesis and release of progesterone
>there are differences among species reflected in anatomical relationship of utero-ovarian vessels (IFN-tau, human choriogonadotropin, PGE, equine choriogonadotropin, estrogen)

Question 9

If uterine horns are removed?

Answer 9

-intact uterus= 15-17day CL lifespan
-no uterus=CL will survive for 148days
-uterus removed contralateral to CL=CL 15-17days
-uterus removed ipsilateral (same side)= CL will have longer lifespan than normal 35days
*indicates importance of same side uterus

Question 10

Blood supply distribution to uterus for different species

Answer 10

-Carnivores: 2 blood vessels
-All other species: 3 blood vessels

Question 11

Blood vasculature

Answer 11

1.Ovarian Artery
-in all species
-has ovarian and uterine branches
2.Vaginal artery
-in all species
-off internal iliac artery or internal pudendal artery
3.Uterine Artery
-not in carnivores??? Maybe wrong
-branch off of internal iliac artery

Question 12

Ovarian artery and uterine vein in ruminants

Answer 12

-wrapped around each other, increasing SA for counter current exchange between uterine drainage and ovarian supply
*prostaglandin comes through uterine vein and is directly transported across blood vessels back into ovarian artery to the ovary

Question 13

Utero-ovarian vasculature in mares

Answer 13

-not the same as ruminants
-instead depends on systemic circulation
-more sensitive to prostaglandin

Question 14

Canine utero-ovarian vasculature

Answer 14

-After ovulation, they consider themselves pregnant= pseudopregnant
>means corpus luteum will stay whether they are actually pregnant or not for the duration of the pregnancy. Does not pay attention to prostaglandin signals

Question 15

Sow utero-ovarian vasculature

Answer 15

-use both a local utero-ovarian pathway and systemic pathway to transport prostaglandin (mix of mare and ruminant)

Question 16

Embryonic development

Answer 16

-Cleavage
-Hatching
-Growth (growth after hatching is different in different species)

Question 17

Bovine embryo

Answer 17

-embryo is more oval
-Uterine PGF2alpha reaches the ovary by an ipsilateral transfer mechanism
-the embryo elongates to fill the uterine horn (ipsilateral to CL) to signal its presence

Question 18

Equine embryo

Answer 18

-round embryo
-Uterine PGF2alpha reaches the ovaries by a systemic route
-no elongation- active mobility throughout the uterus to signal its presence
-embryonic capsule maintains a spherical shape that activates its own mobility (PG secretion)

Question 19

Sows embryo

Answer 19

-Utero-ovarian relationship similar to sheep and cow but MRP involves both local and systemic pathway
>needs at least 4 conceptuses in total and both horns to have conceptuses
>embryo distribution 50-50 in each horn
-if embryo loss occurs after Day 14, CL will not regress

Question 20

MRP timing for ewe, sow, cow, mare

Answer 20

-Ewe- day 12 by IFN-tau)
-Sow Day 13 by estradiol
- Cow Day15-17 by IFN-tau
-Mare day 14-16 by proteins, PGE, estrogens

Question 21

Embryonic strategy for ewe, sow, cow, mare

Answer 21

-ewe &cow = trophoblast elongation
-Sow= elongation and distribution (day 13-17)
-mare = spherical mobility phase (day 9-15)
-cats and dogs= spherical to the time of attachment (little to no elongation)

Question 22

End of embryo stage ewe, sow, cow, mare

Answer 22

Ewe- 35 days
Cow- 45 days
Mare- 55 days

Question 23

Early attachment for ewe, sow, cow, mare

Answer 23

Ewe- 20 days
Sow-70days
Cow- 30days
Mare- 70days

Question 24

MRP in llamas

Answer 24

-MRP signal needs to be sent early (8days) for embryo elongation because the CL breaks down early