Parturition Endocrine Control - Anatomy & Physiology

Regulation of Prostaglandins

The uterus is an important site of prostaglandin synthesis. During pregnancy, the presence of the foetus inhibits the production of prostaglandins in order to prevent luteolysis. At parturition, an increase in prostaglandin synthesis is required.

• Prostaglandins are synthesized from Arachadonic Acid, which is derived from Glycerophospholipids by the enzyme Phospholipase A2 (PLA2).
  • Oestrogen liberates Phospholipase A2 from lysosomes.
  • Progesterone stabilises lysosomes, so Phospholipase A2 cannot be liberated from lysosomes.
• An increase in Oestrogen:Progesterone ratio increases prostaglandin production.
• The increase in Oestradiol (bioactive oestrogen) also increases expression of endometrial Oxytocin receptors.

Regulation of Oxytocin

Details of Oxytocin Synthesis and Secretion may be found here