What is the Origin of GnRH Surge?

The term combines the hormone's acronym, GnRH, with "surge," meaning a sudden, powerful forward movement. Its discovery and characterization were pivotal in reproductive endocrinology, establishing the hypothalamic-pituitary-gonadal (HPG) axis as a hierarchy of control. This event is a classic example of a positive feedback loop in action.

What is the Mechanism of GnRH Surge?

The surge is initiated when rising estrogen levels, produced by the developing ovarian follicle, cross a critical threshold and switch from exerting negative feedback to positive feedback on the hypothalamic GnRH neurons. This intense positive feedback dramatically increases the frequency and amplitude of GnRH pulses, which, in turn, causes the massive release of LH from the pituitary, ultimately leading to follicular rupture and the release of the ovum.

GnRH Surge ∞ Area

GnRH Surge

Meaning

A sudden, massive, and transient increase in the pulsatile secretion of Gonadotropin-Releasing Hormone (GnRH) from the hypothalamus into the hypophyseal portal system. This surge is the physiological trigger for the preovulatory release of Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) from the anterior pituitary gland. The GnRH surge is a central, non-negotiable event required for successful ovulation in the female reproductive cycle.