Prostaglandins are biologically active lipids that help regulate reproductive processes in animals.
Their primary physiological functions are:
1. Luteolysis and Estrus Synchronization.
Following ovulation, the corpus luteum develops and produces progesterone.
Prostaglandins, particularly PGF₂α, directly affect the corpus luteum, leading to:
- Accelerate its regression (luteolysis).
- Shorten the luteal phase of the estrous cycle.
- Allow the next follicular phase to begin earlier.
This helps to coordinate estrus, allowing a group of females to go into heat at the same time.
2. Promotion of Ovulation
Just before ovulation, luteinizing hormone (LH) causes the follicle to release prostaglandins. The prostaglandins:
- Activate enzymes that weaken the follicular wall, such as collagenase and elastase.
- Stimulate contraction of smooth muscle cells within the follicle.
- Facilitate follicular rupture, leading to ovulation.
Externally administered prostaglandins can cause ovulation to occur sooner or later.
3. Induction of Labour
Prostaglandins also influence pregnancy and parturition. Their effects include:
- Accelerating luteolysis can reduce progesterone secretion.
- Lowering progesterone levels weakens fetal protective mechanisms.
- Increased uterine contractions.
- Increasing the uterus' sensitivity to oxytocin
- Promoting cervical softening and dilatation.
These combined effects stimulate and assist labour in the mother animal.
4. Enhancing Sperm Transport and Fertilization
Prostaglandins benefit the male reproductive system by:
- Enhancing the capacity of reproductive tubes to carry sperm
- Promoting efficient sperm release.
- Controlling testosterone synthesis by Leydig cells
- Dilating blood arteries in testicular tissue, improving sperm quality.
These factors improve the likelihood of successful fertilization.
