What role does Luteinising Hormone (LH) play in the release of an egg?

Sourav PanNovember 12, 2024

Answered

Luteinizing Hormone (LH) plays a critical role in the process of ovulation, which is the release of a mature egg from the ovary. Here’s a detailed overview of how LH functions in this process:

Role of Luteinizing Hormone (LH) in Ovulation

1. Production and Trigger:
   • LH is produced by the anterior pituitary gland in response to Gonadotropin-Releasing Hormone (GnRH) secreted by the hypothalamus. As estrogen levels rise due to follicular development, they create a positive feedback loop that stimulates a surge in LH levels, known as the LH surge.
2. Timing of the LH Surge:
   • The LH surge typically occurs around day 14 of a standard 28-day menstrual cycle, though this can vary. The surge happens approximately 24 to 36 hours before ovulation and is crucial for triggering the final maturation of the egg and subsequent ovulation.
3. Induction of Ovulation:
   • The LH surge causes several physiological changes within the ovarian follicle:
     • It increases the activity of proteolytic enzymes that weaken the follicular wall, facilitating the rupture of the dominant follicle .
     • LH stimulates the resumption of meiosis in the oocyte, leading to its release .
     • It promotes luteinization, transforming the ruptured follicle into the corpus luteum, which will later produce progesterone .
4. Post-Ovulation Effects:
   • After ovulation, LH continues to play a role by supporting the corpus luteum’s function. The corpus luteum secretes progesterone, which is essential for preparing the uterine lining for potential implantation of a fertilized egg .
5. Feedback Mechanisms:
   • Following ovulation, if fertilization does not occur, progesterone levels will eventually decline, leading to a drop in LH levels as well. This decrease allows for the initiation of a new menstrual cycle as FSH begins to rise again to recruit new follicles