T4: Maternal Recognition Flashcards
What Is MRP
biochemical signal that prevents luteolysis, results in the maintenance of pregnancy
what does the conceptus present graph look like
during the critical period, the conceptus “notifies” the dam of its presence. Progesterone is maintained and sustained the entire time-horizontal
what is luteotrophic
-functioning to increase the lifespan of the CL
-usually acts directly on the CL
-gonadotropin=LH
-stimulates growth
what is Antiluteolytic
-functioning to prevent luteolysis by blocking the luteolytic factor
-inhibition of PGF2a
what is the cow/eww MRP
-Embryo produces interferon-tau
-antiluteolytic
-produced by trophoblast cells between D10-21 pregnancy
how does cow/eww MRP work
-IFN-T released from trophoblast
-binds to endometrium
-blocks oxytocin receptor synthesis = decrease in PGF2a
-binds to apical portion of uterine glands
-protein released and help embryo growth
describe what happens in non pregnant cows/ewe normally
-PGF2a produced by ?? acts on corpus luteum
-corpus luteum releases oxytocin
-progesterone is inhibited and luteolysis is maintained
what is the lone antiluteolytic factor of MRP in sheep
INF-T
when is IFNT produced in regards to the luteolytic mechanism begins
IFN-t is produced before luteolytic mechanism begins
when does IFNT production start
about day 10
when does luteolytic mechanism occur
about day 14-16
describe the sow’s MRP
-conceptus produces estrogen
-two conceptuses/ horn required
-no conceptuses in one horn= PGF2a (endocrone)= luteolysis
describe the hormones used in sows MRP
-PGF2a secreted toward uterine lumen (exocrine), not circulation
-Estrogen (+) uterine contractility, helps distribute conceptuses to both horns
describe the mare MRP capsule
- proteins/ estrogen
-conceptus presence prevents luteolysis = endometrial PGF2a production decreases
describe mare MRP motility
-movement of the conceptus is important(must migrate 12-14x on days 12,13,14
-the presence of the egg is the recognition factor: touching the walls of the endometrium
-restriction of movement results in pregnancy failure
what type of factor is involved in mare MRPS
unknown anti-luteolytic factor that inhibits PGF2a
describe human MRP
-hCG
-luteotrophic hormone
-LH-like activity
–binds to LH receptor in CL
–maintains life of CL and P4 production
-production peaks 9-14 weeks of pregnancy
–CL loses function
–switch to placental production
what signal is needed for a bitch or queen
no signal from conceptus is necessary
dog: diestrus length similar to gestation length (CL maintained)
cat: mating induced CL formed; luteal duration same as gestation
what is the summary of the bitch/queen
no pregnancy recognition factor, no critical period for recognition/ time of attachment
what is the summary for the cow
-bIFN-t (BTP-1) is the MRP
-critical period: 15-16 dats
-time of attachment: 18-22
-antiluteolytic
what is the summary for ewe
-oIFN-t(otp-1) is the MRP
-critical period: 13-14
-time of attachment: 15-18
-antiluteolytic
what is the summary for the mare
-3 proteins/ estrogen= ?
-critical period: 12-14
-attachment: 36-38
-unknow anti- luteolytic
what is the summary of the sow
-estrogen is the MRP
-critical period: 11-12
-attachment: 14-18
????
what is the summary for humans
-hCG is the MRP
-critical period: 7-12 days
-attachment: 9-12
-luteotropic hormone
what is the most important factor that needs to happen for pregnancy
maternal recognition of pregnancy must occur prior to luteolysis
what structure in the cow and ewe secretes materials that block the synthesis of uterine oxytocin receptors
blastocysts
what in the sow reroutes PGF2a secreted by the endometrium
estrogen
describe the MRP for sows
-conceptus produced estrogen that serves as the signal for MRP
-PGF2a is produced in large quantities but is rerouted into uterine lumen
how does the rerouting of PGF2a work in sows
-directed to be secreted away from the capillaries and toward the uterine lumen
-luminal PGF2a can’t cause luteolysis
-estrogen increases receptor production for prolactin in the endometrium
-promotes exocrine secretion of PGF2a to the uterine lumen rather than endocrine
what is another important feature for sow MRP
there must be at least two conceptuses present in each uterine horn for pregnancy to be maintained
