What is the primary function of gonadotropin-releasing hormone (GnRH)?

Gonadotropin-releasing hormone (GnRH) plays a crucial role in the regulation of the reproductive system by stimulating the anterior pituitary gland to release two key hormones: follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These hormones are essential for normal reproductive function, as they regulate various processes in both males and females, including the maturation of ovarian follicles, ovulation, and the production of sex hormones like estrogen and testosterone.

Specifically, when GnRH is secreted from the hypothalamus, it travels to the anterior pituitary where it prompts the release of FSH and LH. This mechanism is fundamental to the control of the menstrual cycle in women and spermatogenesis in men, solidifying GnRH's primary function as a regulatory hormone in the reproductive axis.

The other options relate to physiological outcomes that are influenced by FSH and LH, but they do not directly pertain to the primary action of GnRH. For example, the development of breast tissue for lactation is primarily driven by prolactin, growth of pubic and axillary hair is influenced by androgens, and the breakdown of the endometrium occurs as a response to hormonal changes, particularly estrogen and progesterone