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Maternal Recognition of Pregnancy - Anatomy & Physiology (view source)
Revision as of 21:41, 12 September 2008
, 21:41, 12 September 2008no edit summary
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== Ruminants ==
* The free-floating blastocyst produces specific proteins that signal to prevent luteolysis.
* Sheep blastocysts produce ovine interferon tau (OIFN-tau)
* Cattle blastocysts produce bovine interferon tau (BIFN-tau)
* Interferon tau is a small protein produced by trophoblastic cells of the blastocyst.
* It is present in the uterus at day 13-21 after ovulation.
* It is not luteotrophic, so does not enhance progesterone production by the corpus luteum.
* Instead, it binds to the uterine endometrium and inhibits the synthesis of oxytocin receptors.
* In addition to preventing the upregulation of oxytocin receptors, interferon tau binds to the apical portion of uterine glands to promote synthesis of proteins that are critical for embryonic survival pre-implantation.
* As a result, there is no production of the luteolytic factor PGF2α and the corpus luteum is maintained.
* The corpus luteum then produces progesterone to maintain the pregnancy.