18 Questions
What is the main purpose of Maternal Recognition of Pregnancy strategies?
To assure maintenance of the corpus luteum
Which factor secreted by the bovine conceptus inhibits ovarian function?
IFNT
In a nonpregnant cyclic cow, what hormone induces pulsatile secretion of PGF2ɑ?
Oxytocin
What effect does binding of oxytocin have on the endometrium?
Induces pulsatile secretion of PGF2ɑ
Which is a role of elongating conceptus in the process of Maternal Recognition of Pregnancy?
Stimulates PGF2ɑ synthesis
What occurs once the bovine conceptus secretes IFNT?
Prevention of luteolysis
What is the day of pregnancy when implantation starts in bitches?
Day 18
Why is maternal recognition of pregnancy not required according to the text?
Because the duration of luteal phase remains unchanged during pregnancy
What event occurs on Day 21 of pregnancy according to the text?
Crosstalk between the developing conceptus and the endometrium
In which animals does implantation start earlier, bitches or queens?
Queens
What is one reason for the similarity in the duration of the luteal phase between nonpregnant cycles and during pregnancy?
Conceptus-endometrium crosstalk
Why is it important to understand the crosstalk between the developing conceptus and the endometrium?
For successful implantation and pregnancy maintenance
What effect does IFNT have on oxytocin receptors in the endometrium during late diestrus?
Downregulates oxytocin receptors
What is the consequence of IFNT blocking the upregulation of oxytocin receptors in the endometrium?
Decreased pulsatile secretion of PGF2ɑ
What does maternal recognition of pregnancy in ruminants involve blocking?
Pulsatile secretion of PGF2ɑ
In the context of maternal immune system during pregnancy, what is the paradox mentioned?
Surveillance against pathogens
During early embryo development, what structure is involved in elongating the conceptus in the endometrium?
Oviduct
What type of molecules are included in histotroph, which is involved in conceptus development?
Amino acids and minerals
Study Notes
Maternal Recognition of Pregnancy Strategies
- Maternal recognition of pregnancy involves the developing conceptus signaling its presence to prevent luteolysis and maintain the corpus luteum and progesterone secretion.
- In cattle, the elongating conceptus causes the secretion of proteins from uterine glands, which stimulates the synthesis of PGFaa, and prevents luteolysis.
Mechanism of Maternal Recognition in Ruminants
- The conceptus produces IFNT, which blocks the upregulation of oxytocin receptors in the endometrium at late diestrus.
- This prevents the pulsatile secretion of PGF2α by the endometrium, maintaining the corpus luteum and progesterone secretion.
Comparison of Maternal Recognition in Different Species
- In companion animals (bitches and queens), maternal recognition of pregnancy is not required, and the duration of the luteal phase is similar between nonpregnant cycles and during pregnancy.
- Implantation starts on Day 18 in bitches and Day 14 in queens.
Development of the Conceptus
- In cattle, the conceptus elongates, and on Day 21 of pregnancy, it moves to the uterine horn, stimulating the synthesis of PGFaa.
- In sheep, implantation starts on Day 16, and in cattle, it starts on Day 20.
Crosstalk Between the Conceptus and Endometrium
- The developing conceptus and endometrium interact through the secretion of proteins and hormones, such as IFNT and PGFaa, to maintain pregnancy.
- The conceptus produces histotroph, a mixture of amino acids, proteins, saccharides, growth factors, lipids, minerals, ions, and vitamins, which supports its development.
Test your knowledge on the maternal recognition of pregnancy strategies observed in different species, where the developing conceptus signals its presence for the maintenance of the corpus luteum and sustained secretion of progesterone. Explore concepts from Dr. Roger V. Short's work on implantation and the secretion of IFNT by the bovine conceptus as discussed by Ealy and Yang.
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