Role in Parturition
CRH is also synthesized by the placenta and seems to determine the duration of pregnancy.
Levels rise towards the end of pregnancy just before birth and current theory suggests three roles of CRH in parturition:
- Increases levels of dehydroepiandrosterone (DHEA) directly by action on the fetal adrenal gland, and indirectly via the mother's pituitary gland. DHEA has a role in preparing for and stimulating cervical contractions.
- Increases prostaglandin availability in uteroplacental tissues. Prostaglandins activate cervical contractions.
- Prior to parturition it may have a role inhibiting contractions, through increasing cAMP levels in the myometrium.
In culture, trophoblast CRH is inhibited by progesterone, which remains high throughout pregnancy. Its release is stimultated by glucocorticoids and catecholamines, which increase prior to parturition lifting this progesterone block.
Read more about this topic: Corticotropin-releasing Hormone
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